@article{szymanski_hetland_figueiredo_2024, title={Imaging Left-Lateral and Reverse Near-Surface Slip of the 2020 Mw 5.1 Sparta, North Carolina, Earthquake}, url={https://doi.org/10.1785/0120230126}, DOI={10.1785/0120230126}, abstractNote={ABSTRACT Coseismic deformation of the 9 August 2020 Mw 5.1 Sparta, North Carolina, earthquake was captured by an Advanced Land Observing Satellite 2 interferogram, a Sentinel 1A/B interferogram, and differential light detection and ranging (lidar). Owing to the moderate surface deformation compared to the inherent uncertainties of interferometric data, the interferograms suffered from low signal-to-noise ratios, exacerbated by spurious signals arising from the discrepancy in resolution between the interferograms and digital elevation model used during processing. Nevertheless, coseismic slip can be imaged using graph-guided fused LASSO, where LASSO is the least-absolute shrinkage and selection operator—an inverse method that combines sparsity constraints and smoothness regularization—to infer signal from noisy and/or incomplete data. We develop five coseismic slip models, one determined only from the Sentinel 1A/B interferogram, one determined from both interferograms, one determined from all the Interferometric Synthetic Aperture Radar (InSAR) data masking potentially spurious data corresponding to industrial parks, one from lidar 3D displacements only, and one constrained by the masked InSAR and the lidar data. All five models are coseismic slip on a single fault plane, trending northwest–southeast with dips ranging from 41° to 60° to the southwest. Coseismic slip is imaged to be shallow, with predominantly oblique reverse slip extending to about 2 km depth. We find that masking the interferometric data corresponding to the industrial parks yields a coseismic slip model in better concordance with ancillary information about the Sparta earthquake and that the lidar data yield additional constraints on near-surface coseismic slip. We show that our preferred coseismic slip model is consistent with a stress regime that does not depart from an Andersonian thrust regime to a large degree, constraining that the background stress is larger than 20–30 MPa.}, journal={Bulletin of the Seismological Society of America}, author={Szymanski, Eric D. and Hetland, Eric A. and Figueiredo, Paula M.}, year={2024}, month={Aug} } @article{babault_figueiredo_owen_fullea_negredo_arroucau_bodet_charco_driessche_caffee_2024, title={Mantle-related late Cenozoic surface uplift in NW Iberia revealed by 10Be cosmogenic nuclide dating and non-linear river profile inversion}, url={https://doi.org/10.5194/egusphere-egu24-11613}, DOI={10.5194/egusphere-egu24-11613}, abstractNote={During the last decade there has been an increase in the study of transient topography because it gives information about surface uplift history. The onset of transient topography forms after a gain in potential energy which leads to the creation of slopes at the outlet of catchment. It is followed by a wave of transient erosion that propagates upstream along the main river, then across tributaries, and from the tributaries to the hillslopes. Records of incision history such as topographic data and landform dating can be gathered into inversion schemes to reconstruct base-level fall and uplift history. In this study, we employ a reversible jump Markov chain Monte Carlo Bayesian algorithm to perform an inversion of topographic data, landform dates, and erosion rates in order to unravel surface uplift history. By adopting a probabilistic approach, we generate an ensemble of solutions that comprise various combinations of model parameters. This methodology enables us to estimate uncertainties in the timing and amount of changes in uplift rates. In the forward model we use the non-linear analytical solutions of the stream power incision model that states that incision I = KAmSn is simply a function of S, the local channel gradient, and A, drainage area above that point and K incapsulates climatic conditions, geometrical and hydraulic characteristics of the stream, bedrock resistance to erosion. Our inversion is constrained by new river-sands 10Be cosmogenic nuclide data, and by incision rates derived from river terraces from the literature. Millennial scale erosion rates and topographic metrics helps us to calibrate the empirical scaling parameters of the stream power incision law. We apply our model to the Atlantic rivers draining NW Iberia where canyons are incised in low-relief erosional surfaces that developed in the last 100 Ma. We show that the transient topography is compatible with a regional late Cenozoic uplift of several hundreds of meters, most likely in response to a mantle-related continental-scale uplift.}, author={Babault, Julien and Figueiredo, Paula and Owen, Lewis A. and Fullea, Javier and Negredo, Ana and Arroucau, Pierre and Bodet, Ludovic and Charco, María and Driessche, Jean Van Den and Caffee, Marc}, year={2024}, month={Mar} } @inproceedings{geologic and paleoliquefaction constraints on past seismicity in the epicentral area of the 9 august 2020 m5.1 sparta, north carolina, earthquake_2023, booktitle={Geological Society of America}, year={2023}, month={Mar} } @inproceedings{investigations of surface rupture caused by the 2020 mw 5.1 sparta, north carolina, usa earthquake and associated paleoseismology of the little river fault_2023, booktitle={Geological Society of America}, year={2023} } @article{mccalpin_ferrario_figueiredo_livio_gruetzner_pisarska-jamrozy_quigley_reicherter_rockwell_stepancikova_et al._2023, title={New developments in onshore paleoseismic methods, and their impact on Quaternary tectonic studies}, volume={664}, ISSN={["1873-4553"]}, url={https://doi.org/10.1016/j.quaint.2023.03.008}, DOI={10.1016/j.quaint.2023.03.008}, abstractNote={Since the publication of Paleoseismology (2nd Edition) in 2009, there has been no comprehensive survey of new trends in Quaternary tectonics. This paper seeks to remedy that situation, by describing the new technologies and interpretations that arose over the past decade. The major technological advances have been in remote sending, e.g., unpiloted aerial vehicles (drones); airborne laser scanning (lidar); terrestrial laser scanning; 3D topographic surveys from Structure-from-Motion; and satellite geodesy such as D-InSAR. Advances have also been made in dating Quaternary deposits, including single-grain luminescence dating (in the laboratory), and portable optically-stimulated luminescence dating (in the field). Geophysical surveys are now a common component of neotectonic investigations, permitting a more formal, 3D integration of subsurface data with surface data. These techniques have lowered the threshold of recognition to smaller and smaller earthquakes, and allowed detection of off-fault deformation such as distributed faulting and folding. We are now collecting so much data that quality control of coseismic field measurements has become an issue, especially when assembling data sets made of old and new data. Soon this data problem will force a reassessment of our time-honored interpretive paradigms, most of which originated in the 1970s and 80s in the early days of neotectonics.}, journal={QUATERNARY INTERNATIONAL}, author={McCalpin, James and Ferrario, Francesca and Figueiredo, Paula and Livio, Franz and Gruetzner, Christoph and Pisarska-Jamrozy, Malgorzata and Quigley, Mark and Reicherter, Klaus and Rockwell, Thomas and Stepancikova, Petra and et al.}, year={2023}, month={Aug}, pages={59–76} } @inproceedings{surface rupture of the 2020 mw 5.1 sparta, north carolina, usa earthquake and evidence of an active structure with recurrent quaternary deformation_2022, booktitle={11th International INQUA Meeting on Paleoseismology, Active Tectonics and Archeoseismology (PATA)}, year={2022}, month={Sep} } @article{the mw 5.1, 9 august 2020, sparta earthquake, north carolina: the first documented seismic surface rupture in the eastern united states_2022, url={https://www.geosociety.org/GSA/Publications/GSA_Today/archive/GSA/GSAToday/archive/32/issues.aspx}, DOI={https://doi.org/10.1130/GSATG517A.1}, abstractNote={At 8:07 a.m. EDT on 9 Aug. 2020 a M w 5.1 earthquake located ~3 km south of Sparta, North Carolina, USA, shook much of the eastern United States, producing the first documented surface rupture due to faulting east of the New Madrid seismic zone.The co-seismic surface rupture was identified along a 2-km-long traceable zone of predominantly reverse displacement, with folding and flexure generating a scarp averaging 8-10-cm-high with a maximum observed height of ~25 cm.Widespread deformation south of the main surface rupture includes cm-dm-long and mm-cmwide fissures.Two trenches excavated across the surface rupture reveal that this earthquake propagated to the surface along a preexisting structure in the shallow bedrock, which had not been previously identified as an active fault.Surface ruptures by faulting are rarely reported for M <6 earthquakes, and hence the Sparta earthquake provides an opportunity to improve seismic hazard knowledge associated with these moderate events.Furthermore, this earthquake occurred in a very low strain rate intraplate setting, where earthquake surface deformation, regardless of magnitude, is sparse in time and rare to observe and characterize.}, journal={GSA Today}, year={2022}, month={Mar} } @inbook{figueiredo_rockwell_2022, title={Application of Coastal Landforms to Active Tectonic Studies}, volume={2}, url={https://dx.doi.org/}, DOI={https://doi.org/10.1016/B978-0-12-818234-5.00163-2}, abstractNote={Coastal landforms at much higher elevations than the current sea level have long been recognized, and inferred to be evidence for past sea-levels and uplift. Despite this clear observation and correct association, the mechanisms that explained the relative sea-level change frequently were not fully understood. Marine terraces and coral reef tracts are commonly present in most coastlines and are frequently preserved as sequences that can be present either locally or regionally. The relative position of these landforms with respect to modern sea level is a valuable marker to infer crustal deformation that can be caused by different forces, such as tectonics or isostatic adjustments. The characterization of these coastal landforms and sediments requires a detailed geomorphic analysis and interpretation of past sea-level positions, which should take modern analogs into consideration. Improvements on their morphologic and absolute elevation characterization were accomplished using remote sensing techniques and high-resolution positioning equipment, and recent developments have improved characterization of submerged landforms. Depending on the type of coastal landforms and predominance of sediments and/or fossil content versus erosional features, several geochronologic methods can be applied to provide a numerical age and allow for the estimation of vertical deformation rates. Calculation of tectonic deformation rates should take into consideration crustal isostatic adjustments that can derive from loading and unloading caused by glaciers, sediments or thick water columns.}, booktitle={Treatise of Geomorphology, 2nd edition}, publisher={Elsevier, Academic Press}, author={Figueiredo, P.M. and Rockwell, T.K.}, editor={Shroder, J.J.F.Editor}, year={2022}, pages={443–476} } @article{karlsson_rockwell_fletcher_figueiredo_cambron rosas_gontz_naik_lacan_spelz_owen_et al._2021, title={Large Holocene ruptures on the Canada David detachment, Baja California, Mexico; implications for the seismogenesis of low-angle normal faults}, volume={570}, ISSN={["1385-013X"]}, url={https://doi.org/10.1016/j.epsl.2021.117070}, DOI={10.1016/j.epsl.2021.117070}, abstractNote={We present the results of detailed mapping and paleoseismic investigations along a section of the complex fault scarp array associated with the Cañada David detachment, a low-angle oblique normal fault that controls the southwestern flank of the Sierra El Mayor, Baja California, Mexico. We used high-resolution unmanned aerial vehicle imagery to map portions of a sequence of alluvial fans that comprise a bajada that flanks the southwestern range front. Their ages are distinguished based on a regional soil chronosequence. Three paleoseismic trenches were excavated across active surface faults that root into the Cañada David detachment at depth. Fine-grained stratigraphic units in the trenches were dated by optically stimulated luminescence techniques. The three trenches in this study show strong evidence for four large (Mw≥7) Holocene earthquakes at or just prior to about 1.7, 4.3–6.1, 7.7–7.6 and 8.4–10.7 ka, as well as weak to moderate evidence for two additional late Pleistocene earthquakes at or just prior to 12.7–14.1 ka and 15.2 ka, indicating an average recurrence of such events of ∼3 ka. This earthquake recurrence interval is slightly longer than that for the Laguna Salada fault to the north that flanks the Sierra Cucapah. The regular recurrence of major surface ruptures strongly suggests that severely-misoriented low-angle normal faults like the Cañada David detachment have a mechanical behavior that is very similar to other more optimally oriented faults suggesting that earthquakes on such faults should be common and may be difficult to recognize from seismologic methods due rolling-hinge ramps and/or multifault ruptures.}, journal={EARTH AND PLANETARY SCIENCE LETTERS}, publisher={Elsevier BV}, author={Karlsson, Keene W. and Rockwell, Thomas K. and Fletcher, John M. and Figueiredo, Paula M. and Cambron Rosas, Jaziel Froylan and Gontz, Allen M. and Naik, Sambit Prasanajit and Lacan, Pierre and Spelz, Ronald M. and Owen, Lewis A. and et al.}, year={2021}, month={Sep} } @article{rimando_schoenbohm_ortiz_alvarado_venerdini_owen_seagren_figueiredo_hammer_2021, title={Late Quaternary Intraplate Deformation Defined by the Las Chacras Fault Zone, West-Central Argentina}, volume={40}, ISSN={["1944-9194"]}, url={https://doi.org/10.1029/2020TC006509}, DOI={10.1029/2020TC006509}, abstractNote={AbstractSeveral major (up to MW 7.5) earthquakes over the past 320 years have shaken the thick‐skinned Sierras Pampeanas region of Argentina, despite exhibiting much lower GPS‐shortening rates than across the thin‐skinned Precordillera region to its west. Whether geodetic shortening rates indicate an actual long‐term shortening gradient, and whether shortening rates translate to higher uplift rates due to steeper faults in the Sierras Pampeanas, remain uncertain due to the limited spatio‐temporal coverage and the inherently large error in the vertical component of deformation of GPS measurements. We measure geomorphic offsets and use 10Be terrestrial cosmogenic nuclide surface exposure dating to determine slip rates on the Las Chacras Fault Zone (LCFZ)—an ∼30 km long, NNW‐trending, steeply dipping (55–65°E) reverse fault that branches off of the longest, westernmost, thick‐skinned Valle Fértil range‐front fault in the western Sierras Pampeanas. Average shortening and uplift rates measured on the LCFZ are ∼0.2 and ∼0.3–0.4 mm/yr, respectively. Despite an uplift rate similar to most other faults in the region, the LCFZ shortening rate is lower than faults to its west; this is in agreement with the inferred west‐east decrease in shortening rates from GPS data, indicating consistent regional deformation patterns since the Late Pleistocene. The decrease in shortening to the east coincides spatially with the termination of the flat portion of the subducted Nazca plate between 67 and 68°W. From scaling relationships among magnitude, slip rate, and fault length, the LCFZ is capable of generating earthquakes of MW 6.7–7.1.}, number={4}, journal={TECTONICS}, author={Rimando, Jeremy M. and Schoenbohm, Lindsay M. and Ortiz, Gustavo and Alvarado, Patricia and Venerdini, Agostina and Owen, Lewis A. and Seagren, Erin G. and Figueiredo, Paula Marques and Hammer, Sarah}, year={2021}, month={Apr} } @inproceedings{multidisciplinary quaternary deformation analysis in a complex low tectonic setting the example of sw portugal_2021, booktitle={2021 Seismological Society of America}, year={2021}, month={Apr} } @inbook{kondo_owen_figueiredo_2022, title={Paleoseismological Studies}, volume={2}, url={http://dx.doi.org/10.1016/b978-0-12-818234-5.00156-5}, DOI={10.1016/b978-0-12-818234-5.00156-5}, abstractNote={Paleoseismology utilizes aspects of tectonic geomorphology, structural geology, sedimentology, and stratigraphy to determine the location, timing, and displacement of past earthquakes. Most studies concentrate on providing data on late Quaternary earthquakes to extend the historical seismic record. Recent methodological developments, including remote sensing, geodesy, fault trenching, and numerical dating, have helped accelerate knowledge and study of past earthquakes. Paleoseismic studies include on-fault and off-fault investigations. The former involves mapping active fault traces including directly displaced landforms and fault trenching. Off-fault studies mainly include studies across the broader seismogenic area, studying and examining paleoliquefaction features, earthquake-triggered landslides, and tsunami and subaqueous deposits as well as vertical variations of deformed landforms as marine terraces and coral-reef tracts, river terraces and drainages anomalies. Seismic hazard analysis is concerned with the long-term forecast of large earthquakes and/or determining or estimating the amount of ground motion expected during a future earthquake. Effective seismic hazard mapping includes developing ground acceleration maps based on high resolution, detailed geomorphic, and Quaternary geologic mapping. Recent studies on modern earthquakes provided additional knowledge on earthquake fault rupture and surficial deformation. Significant future challenges for paleoseismology include reconstructing the timing and magnitude of past earthquakes beyond a few tens of thousands of years to enhance understanding of the nature of seismicity with long recurrence intervals, recognize how neighboring faults interact during seismic cycles and improve regional seismic cycles models, and integrate new knowledge contributing to updating current fault-calling relationships, all crucial for probabilistic analysis of seismic hazard and effective mitigation.}, booktitle={Treatise of Geomorphology, 2nd edition}, publisher={Elsevier, Academic Press}, author={Kondo, H. and Owen, L.A. and Figueiredo, P.M.}, editor={Shroder, J.J.F.Editor}, year={2022}, pages={495–562} } @misc{recorded presentation of multidisciplinary quaternary deformation analysis in a complex low tectonic setting - the example of sw portugal, europe, seismological society of america_2021, url={https://www.youtube.com/watch?v=yGBwWwP5vXg}, year={2021} } @inbook{figueiredo_nash_2022, title={Tectonic Geomorphology of Normal Faults and Their Scarps}, volume={2}, url={https://dx.doi.org/10.1016/}, DOI={https://doi.org/10.1016/B978-0-12-818234-5.00203-0}, abstractNote={A seismogenic fault capable of generating moderate to large earthquakes can actively displace topography repeatedly through time, and can condition surface processes helping form new landscapes. When faults rupture Earth's surface, they generally produce scarps, which are the most common landforms associated with normal faulting. The scarps are the emerged (exhumed) fault plane and are recognized as planar features, with variable dips and heights. Fault scarps can be the product of more than one earthquake and may form a complex morphology in rock or unconsolidated materials. Fault scarps generated during normal faulting of unconsolidated or poorly consolidated materials tend to have a relatively simple initial morphology. These types of fault scarps are common in alluvial fans located along mountain fronts. Such fault scarp result from horizontal tensional stress and, in frictional materials, will have initial dipangles of around 60°. However, as the initial scarp retreats, the degradation of the upper part progressively buries their base with an apron of colluvial debris at the angle of repose. The rate of the fault scarp degradation may be applied to determine the time elapsed since the burial of the initial normal fault scarp by examining the change in morphology of the scarp as its height varies along its length. Fault scarps in consolidated sediments or bedrock are preserved well in the landscape, recording evidence for individual earthquakes. Dating these faults enables the determination of short and long-term slip rates, timing of individual earthquakes, and the amount of displacement per event.}, booktitle={Treatise of Geomorphology, 2nd edition}, publisher={Elsevier, Academic Press}, author={Figueiredo, P.M. and Nash, D.}, editor={Shroder, J.J.F.Editor}, year={2022}, pages={404–428} } @inproceedings{the kinematic evolution of transpression in the eastern california shear zone_2021, booktitle={American Geophysical Union Fall Meeting}, year={2021}, month={Dec} } @inproceedings{active tectonics in sw portugal - quaternary deformation analysis in a low tectonic rate area_2020, booktitle={Geological Society of America}, year={2020}, month={Oct} } @article{nyland_nelson_figueiredo_2020, title={Cosmogenic Be-10 and Cl-36 geochronology of cryoplanation terraces in the Alaskan Yukon-Tanana Upland}, volume={97}, ISSN={["1096-0287"]}, url={http://dx.doi.org/10.1017/qua.2020.25}, DOI={10.1017/qua.2020.25}, abstractNote={ABSTRACTCryoplanation terraces are prominent but enigmatic landforms found in present and past periglacial environments. Geomorphologists have debated for more than a century over processes involved in the formation of these elevated, step-like, bedrock features. Presented here are the first numerical surface exposure ages and scarp retreat rates from cryoplanation terraces in the Yukon-Tanana Upland (YTU) in Alaska, part of unglaciated eastern Beringia, obtained from terrestrial cosmogenic nuclides (TCN) in surface boulders. Ages comprise six 10Be TCN ages from two terrace treads near Eagle Summit and six 36 Cl ages from two treads on Mt. Fairplay. Based on these exposure ages, scarps at both locations were last actively eroding from 49 to 22.4 ka. Both locations exhibit time-transgressive development, particularly near scarp-tread junctions. Boulder exposure ages and distances between sampled boulder locations were used to estimate scarp retreat rates of 0.11 to 0.56 cm/yr. These numerical exposure ages presented here demonstrate that the cryoplanation terraces in the YTU are diachronous surfaces actively eroding during multiple cold intervals. With these results, hypotheses for cryoplanation terrace formation are discussed and evaluated for the YTU, including those based on geologic structure, nivation, and the influence of permafrost.}, journal={QUATERNARY RESEARCH}, author={Nyland, Kelsey E. and Nelson, Frederick E. and Figueiredo, Paula M.}, year={2020}, month={Sep}, pages={157–166} } @inproceedings{geomorphic and paleoseismic trenching evidence that the glen helen fault has not experienced surface rupture in the past 2000 years, and implications for slip transfer between the san andreas and san jacinto fault zones_2020, booktitle={Southern California Earthquake Center Annual Meeting}, year={2020} } @article{tian_owen_xu_shen_zhou_figueiredo_2020, title={Geomorphometry and Statistical Analyses of Landslides Triggered by the 2015M(w)7.8 Gorkha Earthquake and theM(w)7.3 Aftershock, Nepal}, volume={8}, ISSN={["2296-6463"]}, DOI={10.3389/feart.2020.572449}, abstractNote={The 2015 M w 7.8 Gorkha earthquake in Nepal and the M w 7.3 aftershock triggered at least 22,914 landslides that each had areas ≥500 m2 and lengths and widths ≥20 m. Amongst these landslides, 2,059 had areas >10,000 m2. Analyses of the landslide geometry, using length (L), width (W), height (H, from the crown to toe), reach angle (arctan value of H/L), and aspect ratio (L/W), show that most of the landslides have aspect ratios of 1.6–3.6 and reach angles of 35–45°. The fitting relationship between H and L is H = 0.87L − 11.11. The steep topography is likely the main factor that controls the landslide runout and planar shape. The landslides are divided into 3 geomorphometric categories using the aspect ratio: LS1 (L/W ≤ 2); LS2 (2 < L/W ≤ 4); and LS3 (L/W > 4). Statistical analyses of these categories with the control factors show that the landslide distribution does not relate to the three large-scale geologic faults that traverse the region, roads, accumulative precipitation before the earthquakes, and the small earthquakes that occurred during the 2012–2015 pre-monsoons in the study area. The 3 landslide categories are sensitive to similar conditions related to curvature, slope position, lithology, and peak ground acceleration. In contrast, the effects of elevation, slope angle, slope aspect, and streams on landslide distribution differ. Moreover, massive landslides (with areas >10,000 m2) are more likely to occur on the steeper hill slopes that in the higher elevation settings, which provide more substantial gravitational potential energy and long-runout space. As landslides with different geomorphometric shapes have various susceptible conditions, examining the landslide distribution based on their geometric characteristics provides a new way to study the landslide extent and mechanism.}, journal={FRONTIERS IN EARTH SCIENCE}, author={Tian, Yingying and Owen, Lewis A. and Xu, Chong and Shen, Lingling and Zhou, Qing and Figueiredo, Paula Marques}, year={2020}, month={Sep} } @article{tian_owen_xu_ma_li_xu_figueiredo_kang_guo_wang_et al._2020, title={Landslide development within 3 years after the 2015 M-w 7.8 Gorkha earthquake, Nepal}, volume={17}, ISSN={["1612-5118"]}, url={http://dx.doi.org/10.1007/s10346-020-01366-x}, DOI={10.1007/s10346-020-01366-x}, number={5}, journal={LANDSLIDES}, author={Tian, Yingying and Owen, Lewis A. and Xu, Chong and Ma, Siyuan and Li, Kang and Xu, Xiwei and Figueiredo, Paula Marques and Kang, Wenjun and Guo, Peng and Wang, Siyu and et al.}, year={2020}, month={May}, pages={1251–1267} } @inproceedings{late pleistocene and holocene paleoseismology and deformation rates of the pleasant valley fault (nevada, usa)_2020, booktitle={10th International INQUA Meeting on Paleoseismology, Active Tectonics and Archeoseismology PATA (online)}, year={2020} } @inproceedings{preliminary observations of mw 5.1 sparta (north carolina) surface deformation – a first documented mw 5 instrumental earthquake surface rupture in eastern usa?_2020, booktitle={Southern California Earthquake Center Annual Meeting}, year={2020} } @misc{recorded presentation active tectonics in sw portugal - quaternary deformation analysis in a low tectonic rate area gsa 2020_2020, url={https://www.youtube.com/watch?v=r1WBpeE3hcI&t=6s}, year={2020}, month={Oct} } @inproceedings{surface deformation associated with the mw 5.1 sparta, nc, earthquake, late breaking session current understanding of intraplate seismicity and surface deformation associated with the august 9th, 2020 mw 5.1 earthquake near sparta, north carolina_2020, booktitle={Geological Society of America}, year={2020}, month={Oct} } @inproceedings{surface rupture of the little river fault in response to the august 9, 2020 mw 5.1 earthquake near sparta, north carolina _2020, booktitle={Southern California Earthquake Center Annual Meeting}, year={2020} } @article{gold_behr_fletcher_rockwell_figueiredo_2020, title={Time‐Invariant Late Quaternary Slip Rates Along the Agua Blanca Fault, northern Baja California, Mexico}, volume={39}, url={http://dx.doi.org/10.1029/2019tc005788}, DOI={10.1029/2019tc005788}, abstractNote={AbstractFault slip rates inform models of strain accumulation and release, which over geologic time may vary or remain constant depending on factors like structural complexity, fault strength, deformation rates, and proximity to other faults. In this study, we present a Late Pleistocene–Holocene slip history based on four new geologic slip rates for the Agua Blanca Fault (ABF), which transfers Pacific‐North American dextral plate boundary motion across the Peninsular Ranges of northern Baja California. Time‐averaged slip rates from three sites are 2.8 + 0.8/−0.6 mm/a since ~65.1 ka, 3.0 + 1.4/−0.8 mm/a since ~21.8 ka, 3.2 + 1.0/−0.6 mm/a since ~12.5 ka, and 3.5 + 5.1/−2.0 mm/a since ~1.4 ka; however, the actual slip rate may be closer to 4 mm/a when off‐fault slip and age interpretation uncertainties are considered. Significantly, although the ABF has more in common in terms of length, net offset, and slip rate with known variable slip rate faults, the most straightforward age and offset interpretations for the ABF suggest constant slip rates over ~10 kyr time scales. As with other constant slip rate faults, comparable neighboring faults that might modulate the ABF slip rate are absent, suggesting that fault interaction, or lack thereof, may be a more significant factor controlling fault behavior on this and potentially other faults. The new rates indicate that the ABF accommodates at least half of total slip across the Peninsular Ranges, clarifying strain partitioning for seismic forecasting models that previously lacked modern geologic slip rate constraints for this domain of the plate boundary.}, number={9}, journal={Tectonics}, publisher={American Geophysical Union (AGU)}, author={Gold, P. O. and Behr, W. M. and Fletcher, J. M. and Rockwell, T. K. and Figueiredo, P. M.}, year={2020}, month={Aug} } @inproceedings{understanding of intraplate seismicity and surface deformation associated with the august 9th, 2020 mw 5.1 earthquake near sparta, north carolina_2020, booktitle={Geological Society of America 2020 Meeting}, year={2020} } @inproceedings{controls on 10be-derived basin-wide erosion rates in the south-central andes: a multivariate bayesian approach_2019, booktitle={American Geophysical Union Fall Meeting}, year={2019}, month={Dec} } @inproceedings{cross-correlation of osl, 14 c and 10 be dating methods applied to active tectonic studies on the banning strand of the san andreas fault_2019, booktitle={13th New World Luminescence Workshop}, year={2019}, month={Aug} } @unpublished{data management for gis _2019, url={https://scholar.uc.edu/show/8623j016z}, DOI={10.7945/2TCP-0K64}, year={2019} } @inproceedings{kinematic models for the development of the eastern california shear zone, mojave desert_2019, booktitle={Geological Society A merica Annual Meeting}, year={2019}, month={Oct} } @inproceedings{late quaternary deformation and recency of faulting of the northernmost san jacinto fault zone, and implications for slip transfer to san andreas fault._2019, year={2019}, month={Aug} } @inproceedings{late quaternary intraplate deformation: the las chacras fault zone (lcfz), west-central argentina_2019, booktitle={American Geophysical Union Fall Meeting}, year={2019} } @article{late quaternary slip rates for faults of the central walker lane (nevada, usa): spatiotemporal strain release in a strike-slip fault system_2018, url={http://dx.doi.org/10.1130/ges02088.1}, DOI={10.1130/ges02088.1}, abstractNote={Abstract The Walker Lane is a broad shear zone that accommodates a significant portion of North American–Pacific plate relative transform motion through a complex of fault systems and block rotations. Analysis of digital elevation models, constructed from both lidar data and structure-from-motion modeling of unmanned aerial vehicle photography, in conjunction with 10Be and 36Cl cosmogenic and optically stimulated luminescence dating define new Late Pleistocene to Holocene minimum strike-slip rates for the Benton Springs (1.5 ± 0.2 mm/yr), Petrified Springs (0.7 ± 0.1 mm/yr), Gumdrop Hills (0.9 +0.3/−0.2 mm/yr), and Indian Head (0.8 ± 0.1 mm/yr) faults of the central Walker Lane (Nevada, USA). Regional mapping of the fault traces within Quaternary deposits further show that the Indian Head and southern Benton Springs faults have had multiple Holocene ruptures, with inferred coseismic displacements of ∼3 m, while absence of displaced Holocene deposits along the Agai Pah, Gumdrop Hills, northern Benton Springs, and Petrified Springs faults suggest they have not. Combining these observations and comparing them with geodetic estimates of deformation across the central Walker Lane, indicates that at least one-third of the ∼8 mm/yr geodetic deformation budget has been focused across strike-slip faults, accommodated by only two of the five faults discussed here, during the Holocene, and possibly half from all the strike-slip faults during the Late Pleistocene. These results indicate secular variations of slip distribution and irregular recurrence intervals amongst the system of strike-slip faults. This makes the geodetic assessment of fault slip rates and return times of earthquakes on closely spaced strike-slip fault systems challenging. Moreover, it highlights the importance of understanding temporal variations of slip distribution within fault systems when comparing geologic and geodetic rates. Finally, the study provides examples of the importance and value in using observations of soil development in assessing the veracity of surface exposure ages determined with terrestrial cosmogenic nuclide analysis.}, journal={Geosphere}, year={2018}, month={Nov} } @inproceedings{long term slip rate of camp rock fault (eastern california shear zone) and implications for the regional understanding of geological rate_2019, booktitle={American Geophysical Union Fall Meeting}, year={2019} } @misc{paleoseismology - creating a grid for reference_2019, url={https://www.youtube.com/watch?v=Y-6QR01jlCg}, year={2019}, month={Oct} } @misc{paleoseismology trenching across the pleasant valley -part 1_2019, url={https://www.youtube.com/watch?v=eKRISRVhWDQ}, year={2019}, month={Oct} } @misc{paleoseismology trenching across the pleasant valley fault - part 2_2019, url={https://www.youtube.com/watch?v=eKRISRVhWDQ}, year={2019}, month={Oct} } @inproceedings{pleistocene rapid decrease in extensional exhumation of the diancang shan implies tectonic changes in se tibet_2019, booktitle={American Geophysical Union Fall Meeting}, year={2019} } @inproceedings{preliminary geochronology data for cajon pass terraces- implications to the regional chronosequence_2019, booktitle={Southern California Earthquake Center Annual Meeting}, year={2019}, month={Aug} } @inproceedings{uniform late quaternary slip rate along the jinghong fault, se of the eastern himalayan syntaxis_2019, booktitle={16th Annual Meeting of Asian Oceania Geosciences Society,}, year={2019}, month={Jun} } @inproceedings{uniform late quaternary slip rate along the jinghong fault, se of the eastern himalayan syntaxis, gsa_2019, booktitle={. Geological Society of America}, year={2019}, month={Oct} } @inproceedings{using uav-mounted lidar surveys to investigate potential slip rate sites along the northernmost san jacinto fault zone near its junction with the san andreas fault in the cajon pass area, california_2019, booktitle={Southern California Earthquake Center Annual Meeting}, year={2019}, month={Aug} } @article{xie_gallant_wetmore_figueiredo_owen_rasmussen_malservisi_dixon_2019, title={A new geological slip rate estimate for the Calico Fault, eastern California: implications for geodetic versus geologic rate estimates in the Eastern California Shear Zone}, volume={61}, url={https://doi.org/10.1080/00206814.2018.1531272}, DOI={10.1080/00206814.2018.1531272}, abstractNote={ABSTRACT Accurate estimation of fault slip rate is fundamental to seismic hazard assessment. Previous work suggested a discrepancy between short-term geodetic and long-term geologic slip rates in the Mojave Desert section of the Eastern California Shear Zone (ECSZ). Understanding the origin of this discrepancy can improve understanding of earthquake hazard and fault evolution. We measured offsets in alluvial fans along the Calico Fault near Newberry Springs, California, and used several techniques to date the offset landforms and determine a slip rate. Our preferred slip rate estimate is 3.2 ± 0.4 mm/yr, representing an average over the last few hundred thousand years, faster than previous estimates. Seismic hazard associated with this fault may therefore be higher than previously assumed. We discuss possible biases in the various slip rate estimates and discuss possible reasons for the rate discrepancy. We suggest that the ECSZ discrepancy is an artefact of limited data, and represents a combination of faster slip on the Calico Fault, off-fault deformation, unmapped fault strands, and uncertainties in the geologic rates that have been underestimated. Assuming our new rate estimate is correct and a fair amount (40%) of off-fault deformation occurs on major ECSZ faults, the summed geologic rate estimate across the Mojave section of the ECSZ is 10.5 ± 3.1 mm/yr, which is equivalent within uncertainties to the geodetic rate estimate.}, number={13}, journal={International Geology Review}, publisher={Informa UK Limited}, author={Xie, Surui and Gallant, Elisabeth and Wetmore, Paul H. and Figueiredo, Paula M. and Owen, Lewis A. and Rasmussen, Craig and Malservisi, Rocco and Dixon, Timothy H.}, year={2019}, month={Sep}, pages={1613–1641} } @article{active tectonics in the cheb basin: youngest documented holocene surface faulting in central europe?_2019, url={http://dx.doi.org/10.1016/j.geomorph.2018.11.007}, DOI={10.1016/j.geomorph.2018.11.007}, abstractNote={The NNW-SSE trending Mariánské Lázně Fault (MLF) zone is situated in the western part of the Bohemian Massif (Czech Republic, central Europe) and controls the eastern limit of Cenozoic Cheb Basin. The Cheb Basin is well-known for present-day earthquake swarms, with maximum magnitude not exceeding Mw 4.0, and abundant occurrences of mantle-derived carbon-dioxide emanations. The MLF borders the Cheb Basin towards the Krušné hory Mts. controlling their morphologically pronounced mountain front. However, no large earthquakes required for forming the tectonic morphology (Mw > 6) have been recorded historically. To examine if potential pre-historic earthquakes contributed to mountain front formation along the MLF and to Late Quaternary seismic hazard in the region, we excavated a trench at the Kopanina site where the fault was identified by geomorphological and geophysical surveys. The trench revealed repeated movements along several fault strands within the MLF of various ages, which displaced basin sediments deposited since the Oligocene. The youngest faults cut and deformed Holocene layers at least twice, with a total cumulative vertical displacement on the main fault 0.5 m. The deformations that we documented here suggest transpression within the MLF during Holocene. Based on empirical relationships between magnitude and displacement/rupture length, the MLF has produced earthquakes with a minimum magnitude of Mw = 6.5. The youngest event is dated approximately to the period 792–1020 CE. To match the youngest event with a historical earthquake, several candidates could be considered and further investigated, but the most probable one seems to be the earthquake reported in catalogs for 998 CE. Hence our study revealed the youngest proven surface faulting in central Europe and the largest Holocene event reported so far for the Bohemian Massif, which is of great importance for seismic hazard re-assessment for the broader, slowly moving region.}, journal={Geomorphology}, year={2019}, month={Feb} } @inproceedings{morphotectonic analysis of the southern portuguese atlantic coastal zone- implications for active tectonics_2018, booktitle={3rd Iberia Meeting on Active Faults and Paleoseismology}, year={2018}, month={Jun} } @article{morphotectonics in a low tectonic rate area: analysis of the southern portuguese atlantic coastal region_2019, url={http://dx.doi.org/10.1016/j.geomorph.2018.02.019}, DOI={10.1016/j.geomorph.2018.02.019}, abstractNote={South Portugal is characterized by low tectonic rates (<0.3 mm/a), with infrequent large seismicity. Recent studies indicate a coastal region in southwest Portugal uplifting at higher rates (0.11 ± 0.01 mm/a) than the remaining southern portion of Portugal (~0.04 mm/a); however, the mechanisms that drive this uplift are poorly understood. With the purpose of investigating the regional Quaternary deformation and its patterns, as well as the difference in the uplift rate, 77 exorheic drainage basins along 460 km of the southern Portuguese coastline were analysed through the application of geomorphic indices. In this study we applied stream channel sinuosity S, basin relief ratio Rh, elongation Re, basin shape ratio Bs, valley height-width ratio Vf, basin asymmetry factor AF, hypsometry HI and, the stream-length gradient index SL, and we propose the terminal basin shape index TBS. This study aims to (1) identify Quaternary deformation along presumed tectonic structures; (2) recognize uplift or subsidence along the coastline; and (3) test the application of geomorphic indices in low deformation rate environments. The cross-correlation of results led to the recognition of the São Teotónio-Aljezur-Sinceira fault system and the São Marcos-Quarteira Fault as major regional Quaternary faults, as well as to the interpretation of Quaternary activity for other structures. Spatial differences in uplift rates are identified through basin shape indices and valley height-width ratios, even for low vertical motion rates, whereas other indices were found to be not as sensitive to variations in uplift rate.}, journal={Geomorphology}, year={2019}, month={Feb} } @inproceedings{on-going holocene slip-rates analysis for the banning strand of the san andreas fault: challenges with estimating slip-rates along a rapidly moving fault_2018, booktitle={9th International INQUA Meeting on Paleoseismology, Active Tectonics and Archaeseismology.}, year={2018}, month={Jun} } @inproceedings{paleoseismology and neotectonics of the southern sierra el mayor, baja california, mexico._2018, booktitle={Southern California Earthquake Center Annual Meeting}, year={2018}, month={Aug} } @inproceedings{pleistocene activity, morphotectonics and seismotectonics of the são teotónio-aljezur-sinceira fault system, southwest portugal_2018, booktitle={3rd Iberia Meeting on Active Faults and Paleoseismology}, year={2018}, month={Jun} } @inproceedings{quaternary differential vertical motion at sw iberia inferred by plio-pleistocene marine terraces and morphotectonics. is there a new kid in the block? _2018, booktitle={9th International INQUA Meeting on Paleoseismology, Active Tectonics and Archaeseismology.}, year={2018}, month={Jun} } @inproceedings{revisiting late pleistocene uplifted marine terraces at south portugal: new geochronology data and its implications_2018, booktitle={9th International INQUA Meeting on Paleoseismology, Active Tectonics and Archaeseismology.}, year={2018}, month={Sep} } @inproceedings{revisiting the cajon pass quaternary terraces with geochronology dating implications for the long-term slip rates of the san jacinto and san andreas systems_2018, booktitle={Southern California Earthquake Center Annual Meeting}, year={2018}, month={Aug} } @article{active tectonics in southern portugal (sw iberia) inferred from gps data. implications on the regional geodynamics_2017, url={http://dx.doi.org/10.1016/j.jog.2017.10.002}, DOI={10.1016/j.jog.2017.10.002}, abstractNote={A GPS-based crustal velocity field for the SW Portuguese territory (Algarve region, SW Iberia) was estimated from the analysis of data from a network of campaign-style GPS stations set up in the region since 1998, complemented with permanent stations, covering an overall period of 16.5 years. The GPS monitoring sites were chosen attending to the display of the regional active faults, in an attempt to detect and monitor any related crustal straining. The residual horizontal velocities relative to Eurasia unveil a relatively consistent pattern towards WNW, with magnitudes that noticeably increase from NNE to SSW. Although the obtained velocity field does not evidence a sharp velocity gradient it suggests the presence of a NW-SE trending crustal shear zone separating two domains, which may be slowly accumulating a slightly transtensional right-lateral shear strain. Based on the WNW velocity differential between the northeastern block and the southwestern block, a shear strain rate accumulation across the shear zone is estimated. This ongoing crustal deformation is taken as evidence that a nearby major active structure, the São Marcos − Quarteira fault, may be presently accumulating strain, therefore being potentially loaded for seismic rupture and the generation of a large magnitude earthquake. Further inferences are made concerning the interseismic dynamic loading of other major onshore and offshore active structures located to the west.}, journal={Journal of Geodynamics}, year={2017}, month={Dec} } @inproceedings{do low-angle normal faults produce large earthquakes? a case study of the cañada david detachment of northern baja california, mexico_2017, booktitle={Southern California Earthquake Center Annual Meeting}, year={2017} } @inproceedings{puzzling results in a slip rate study for the banning strand of the san andreas fault near north palm springs_2017, booktitle={Southern California Earthquake Center Annual Meeting}, year={2017}, month={Aug} } @inproceedings{quaternary rates of slip for faults of the central walker lane_2017, booktitle={Southern California Earthquake Center Annual Meeting}, year={2017}, month={Aug} } @inproceedings{late pleistocene deformation at aljezur fault system, sw portugal: seismicity triggering within a slow tectonic rate setting and relationships with sea-level rise_2016, booktitle={International INQUA Meeting on Paleoseismology, Active Tectonics and Archaeseismology,}, year={2016}, month={Aug} } @inproceedings{slip variability and temporal clustering along the imperial fault at mesquite basin, imperial valley, california, and possible through-going rupture to the san andreas fault_2016, year={2016}, month={Aug} } @inproceedings{work in progress to estimate a latest pleistocene slip rate for the banning strand of the san andreas fault near north palm springs_2016, booktitle={Southern California Earthquake Center Annual Meeting}, year={2016}, month={Aug} } @phdthesis{neotectonic and seismotectonic studies along the southwest portugal sector: implications for the regional seismicity_2015, url={https://repositorio.ul.pt/bitstream/10451/18382/1/ulsd070757_td_Paula_Figueiredo.pdf}, journal={Universidade de Lisboa}, year={2015}, month={May} } @article{neves_cabral_luttrell_figueiredo_rockwell_sandwell_2015, title={The effect of sea level changes on fault reactivation potential in Portugal}, volume={658}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84942550892&partnerID=MN8TOARS}, DOI={10.1016/j.tecto.2015.07.023}, abstractNote={The aim of this study is to assess the impact of sea level changes on both the stress field and the potential of fault reactivation in west Iberia. The analysis is applied to a set of five active faults distributed across Portugal, selected for representing predominant fault directions and for being seismically active. The results show that the rise of sea level since the Last Glacial Maximum has produced flexural effects with distinct impacts on different faults. The Coulomb stress changes induced by the sea level rise along the S. Marcos-Quarteira (south Portugal) and the Horseshoe (offshore SW Iberia) faults are found to be extremely small, independently of the elastic plate thickness. These faults are thus unaffected by flexural effects related to ocean loading, and are unlikely to possess any paleoseismic record of this phenomenon. In contrast, the eustatic sea level rise during the late Pleistocene could have raised the Coulomb stress by 0.5–1 MPa along the Manteigas–Vilariça–Bragança (north Portugal) and Lower Tagus Valley (Lisbon area) fault systems. Such stress perturbations are probably sufficient to impact the seismic cycle of the Manteigas–Vilariça–Bragança fault, bringing it closer to failure and possibly triggering the earthquake clusters that have been observed in previous paleoseismologic studies.}, journal={Tectonophysics}, author={Neves, M.C. and Cabral, J. and Luttrell, K. and Figueiredo, P. and Rockwell, T. and Sandwell, D.}, year={2015}, pages={206–220} } @article{figueiredo_cabral_rockwell_2013, title={Recognition of Pleistocene marine terraces in the southwest of Portugal (Iberian Peninsula): Evidences of regional quaternary uplift}, volume={56}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84899946479&partnerID=MN8TOARS}, DOI={10.4401/ag-6276}, abstractNote={
Southwest mainland Portugal is located close to the Eurasia-Nubia plate boundary and is characterized by moderate seismicity, although strong events have occurred as in 1755 (Mw≥8), 1969, (Mw 7.9), and more recently in 2007 (Mw 5.9) and 2009 (Mw 5.5), all located in the offshore. No historical earthquakes with onshore rupture are known for this region. At the coastline, high sea cliffs, incised drainages, emergent marine abrasion platforms and paleo sea cliffs indicate that this region is undergoing uplift, although no morphological features were found that could be unequivocally associated with the 1755 mega earthquake. To better understand the recent tectonic activity in this sector of Iberia, it is necessary not only to analyze active structures on land, but also to search for evidence for deformation that may relate to inferred offshore active structures. We thus conducted a study of marine terraces along the coastline to identify regional vertical crustal motions. Several poorly preserved surfaces with thin sedimentary deposits, comprising old beach sediments, were recognized at elevations starting at 2 m elevation and rising inland up to a regional abrasion platform situated at about 120 m a.s.l.. We identified distinct paleo sea level references at several locations at consistent elevations. This terrace sequence is likely Late Pleistocene in age, with individual platforms correlative to MIS 5 high stands and is coherent with a long-term slow uplift of the littoral zone for the southwest of Portugal. Although dating of discrete platforms is an ongoing and difficult task, preliminary correlations of paleo-shoreline elevations suggest that the uplift rate is in the range of 0.1-0.2 mm/yr.
}, number={6}, journal={Annals of Geophysics}, author={Figueiredo, P.M. and Cabral, J. and Rockwell, T.K.}, year={2013} } @article{neves_cabral_figueiredo_sandwell_rockwell_luttrell_2014, title={Seismic triggering induced by lithospheric flexure due to eustatic sea level rise | Sismicidade desencadeada em Portugal Continental por flexão litosférica associada a subida eustática do nível do mar}, volume={101}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84939799713&partnerID=MN8TOARS}, journal={Comunicacoes Geologicas}, author={Neves, M.C. and Cabral, J. and Figueiredo, P.M. and Sandwell, D. and Rockwell, T.K. and Luttrell, K.}, year={2014}, pages={913–917} } @article{seismic triggering induced by lithospheric flexure due to eustatic sea level rise | sismicidade desencadeada em portugal continental por flexão litosférica associada a subida eustática do nível do mar_2014, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84939799713&partnerID=MN8TOARS}, journal={Comunicacoes Geologicas}, year={2014} } @article{late pliocene to pleistocene tectonic activity in sw portugal: the s. teotónio-aljezur-sinceira fault system – a review_2012, url={http://www.geol.uniovi.es/TDG/Volumen30/TG30-05.PDF}, journal={Trabajos de Geologia}, year={2012} } @inproceedings{uplifted pleistocene marine terraces at the southwest coast of portugal. is there more than we know?_2012, booktitle={XIX Congrés de Doctorants, Institute de Physique Global du Paris}, year={2012} } @inproceedings{plio- pleistocene tectonic activity in the southwest of portugal_2011, booktitle={2nd INQUA-IGCP 567 Int. Workshop}, year={2011} } @article{cabral_moniz_batlló_figueiredo_carvalho_matias_teves-costa_dias_simão_2013, title={The 1909 Benavente (Portugal) earthquake: Search for the source}, volume={69}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84885021803&partnerID=MN8TOARS}, DOI={10.1007/s11069-011-0062-8}, abstractNote={The Lower Tagus River Valley has been affected by severe earthquakes comprising distant events, as in 1755, and local earthquakes, as in 1344, 1531, and 1909. The 1909 earthquake was located NE of Lisbon, near Benavente, causing serious damage and many losses. Mw 6.0 has been assessed for this earthquake and a reverse faulting focal mechanism solution has been calculated. Poor epicenter location, possible directivity and site effects, low fault slip rates, and the thick Cenozoic sedimentary cover make difficult correlation with regional structures. The focal mechanism indicates an ENE reverse fault as source, though it does not match any outcropping active structure suggesting that the event could have been produced by a blind thrust beneath the Cenozoic sedimentary fill. Hidden sources, inferred from seismic reflection data, are a possible NE structure linking the Vila Franca de Xira and the Azambuja faults, or the southern extension of the later. Evidence of surface rupturing is inhibited by the thick Holocene alluvial cover and the high fluvial sedimentation rate, though a slightly depressed area was identified in the Tagus alluvial plain W of Benavente which was investigated as possible geomorphic evidence of co-seismic surface deformation. A high-resolution seismic reflection profile was acquired across a 0.5 m high scarp at this site, and two trenches were opened across the scarp for paleoseismic research. Some deformation of dubious tectonic origin was found, requiring further studies.}, number={2}, journal={Natural Hazards}, author={Cabral, J. and Moniz, C. and Batlló, J. and Figueiredo, P. and Carvalho, J. and Matias, L. and Teves-Costa, P. and Dias, R. and Simão, N.}, year={2013}, pages={1211–1227} } @inproceedings{towards the development of a long rupture history of the imperial fault in mesquite basin, imperial valley, southern california,_2011, booktitle={Seismological Society of America}, year={2011} } @article{cabral_marques_figueiredo_matias_2011, title={Active surface faulting or landsliding in the Lower Tagus Valley (Portugal)? A solved controversy concerning the Vila Chã de Ourique site}, volume={15}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-79953236965&partnerID=MN8TOARS}, DOI={10.1007/s10950-010-9221-8}, abstractNote={The Lower Tagus Valley has experienced significant (M 6–7) historical seismicity, evidencing the presence of seismogenic faults. These are still deficiently known due to the low strain rates and the recent alluvial sedimentation of the Tagus River that buries most of the structures, though Paleoseismic evidence was allegedly found by a research team in the Tagus valley, at a site 60 km N of Lisbon, near Vila Chã de Ourique (VCO). According to this team, trenching at the VCO site exposed an active thrust fault, evidencing the surface rupture of a large earthquake that occurred in 1531. Our studies performed at this site, comprising field observations with a reappraisal of the trench outcrops previously excavated, borehole drilling, soil mechanics laboratory testing, and seismic reflection acquisition, pointed to the alternative interpretation that the outcropping structures are gravitational and not of tectonic origin. The interpretation of new outcrops crosscutting the structures exposed at the trenches, as well as newly acquired high-resolution seismic reflection data, definitely exclude the active thrust fault explanation and support a gravitational slip model for all the observed structures. Gravitational slip in the river bank slope was promoted by low shear strength clays and high pore water pressure coupled with slope toe river erosion. Gravitational slides must have occurred prior to development of the present sedimentation level of the Tagus alluvial plain, which was attained in the last few thousand years as indicated by borehole data and estimations of sedimentation rates.}, number={2}, journal={Journal of Seismology}, author={Cabral, J.M. and Marques, F. and Figueiredo, P. and Matias, L.}, year={2011}, pages={215–234} } @inproceedings{neotectonics and paleoseismic studies at sw portugal mainland: the s. teotónio- aljezur- sinceira fault system_2010, booktitle={8th Portuguese Geological Congress}, year={2010} } @inproceedings{plio-pleistocene tectonic activity in the southwest of portugal_2010, booktitle={Submarine Paleoseismology: The Offshore Search of Large Holocene Earthquakes, Eur. Sc. Found. Conferences}, year={2010} } @inproceedings{quaternary seismic activity of the vilariça fault (ne portugal): preliminary results of a paleoseismological study_2010, booktitle={8th Portuguese Geological Congress}, year={2010} } @inproceedings{southwest portugal plio-pleistocene tectonic activity studies: the s.teotónio- aljezur - sinceira fault system and coastal tectonic uplift evidences,_2010, booktitle={1st Iberfault, Active Tectonics and Paleoseismology Iberian Meeting}, year={2010} } @inproceedings{actividade tectónica plistocénica no sw de portugal: o sistema de falhas são teotónio – aljezur – sinceira e evidências de levantamento ao longo do litoral._2009, booktitle={VII Meeting Iberian Quaternary, GTPEQ & AEQUA}, year={2009} } @inproceedings{late pliocene to pleistocene tectonic activity in sw portugal: new data from field observations and trenching_2009, booktitle={6th Symposium on the Iberian Atlantic Margin}, year={2009} } @book{rockwell_fonseca_madden_dawson_owen_vilanova_figueiredo_2009, title={Palaeoseismology of the Vilariça segment of the Manteigas-Bragança fault in northeastern Portugal}, volume={316}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-70349173409&partnerID=MN8TOARS}, DOI={10.1144/SP316.15}, abstractNote={Abstract The Manteigas-Bragança fault is a major, 250-km-long, NNE-striking, sinistral strike-slip structure in northern Portugal. This fault has no historical seismicity for large earthquakes, although it may have generated moderate (M5+) earthquakes in 1751 and 1858. Evidence of continued left horizontal displacement is shown by the presence of Cenozoic pull-apart basins as well as late Quaternary stream deflections. To investigate its recent slip history, a number of trenches were excavated at three sites along the Vilariça segment, north and south of the Douro River. At one site at Vale Meão winery, the occurrence of at least two and probably three events in the past 14.5 ka was determined, suggesting an average return period of about 5–7 ka. All three events appear to have occurred as a cluster in the interval between 14.5 and 11 ka, or shortly thereafter, suggesting a return period of less than 2 ka between events within the cluster. In the same area, a small offset rill suggests 2–2.5 m of slip in the most recent event and about 6.1 m after incision below a c. 16 ka alluvial fill event along the Douro River. At another site along the Vilariça River alluvial plain, NE of the Vale Meão site, several trenches were excavated in late Pleistocene and Holocene alluvium, and exposed the fault displacing channel deposits dated to between 18 and 23 ka. In a succession of closely spaced parallel cuts and trenches, the channel riser was traced into and across the fault to resolve c. 6.5 m of displacement after 18 ka and c. 9 m of slip after c. 23 ka. These observations yield a slip rate of 0.3–0.5 mm/a, which is consistent with earlier estimates. Combining the information on timing at Vale Meão winery and displacement at Vilariça argues for earthquakes in the M7+ range, with coseismic displacements of 2–3 m. This demonstrates that there are potential seismic sources in Portugal that are not associated with the 1755 Lisbon earthquake or the Tagus Valley, and, although rare, large events on the Vilariça fault could be quite destructive for the region. This work provides an analogue for the study of active faulting in intracontinental settings and supports the view that earthquakes within intracontinental settings tend to cluster in time. In addition, this study highlights the usefulness and application of multiple field, remote sensing and geochronological techniques for seismic hazard mitigation.}, journal={Geological Society Special Publication}, author={Rockwell, T. and Fonseca, J. and Madden, C. and Dawson, T. and Owen, L.A. and Vilanova, S. and Figueiredo, P.}, year={2009}, pages={237–258} } @inproceedings{s.teotónio- aljezur- sinceira fault system: a seismogenic source at sw portugal?_2009, booktitle={1st SHARE (Seismic Hazard Harmonization in Europe) Iberian Workshop for Active Faults and Seismogenic Sources}, year={2009} } @inproceedings{late pliocene to pleistocene tectonic activity in sw portugal: the s. teotonio-aljezur-sinceira fault system and evidence for coastal uplift._2008, booktitle={American Geophysical Union Fall Meeting}, year={2008}, month={Dec} } @inproceedings{late pliocene to pleistocene tectonic activity in sw portugal: the s. teotónio -aljezur - sinceira fault system – a review_2008, booktitle={1st Inter. Meeting of Young Researchers in Structural Geol. and Tect}, year={2008} } @inproceedings{analysis on the azambuja fault tectonic - a morphotectonic approach._2007, booktitle={1st Young Geosc. Res. Meeting}, year={2007} } @inproceedings{preliminary data on the sedimentary dinamics at carcavelos beach_2007, booktitle={1st Young Geosc. Res. Meeting}, year={2007} } @inproceedings{seismic characterization of the vilariça fault: comparison between a segmentation model and paleoseismology_2007, booktitle={Ass. of Env. & Eng. Geol. Ann. Meeting}, year={2007} } @inproceedings{topographical surface deformation, at vila chã de ourique_2007, booktitle={1st Young Geosc. Res. Meeting}, year={2007} } @inproceedings{carcavelos beach sedimentary dynamics_2006, booktitle={5th Geophysics and Geodesy Portuguese- Spanish Meeting}, year={2006} } @phdthesis{multidisciplinary approach for the seismotectonic study of the tagus lower valley_2006, url={http://repositorio.ul.pt/}, year={2006}, month={Nov} } @article{cabral_ribeiro_figueiredo_pimentel_martins_2004, title={The Azambuja fault: An active structure located in an intraplate basin with significant seismicity (Lower Tagus Valley, Portugal)}, volume={8}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-4344702010&partnerID=MN8TOARS}, DOI={10.1023/B:JOSE.0000038450.23032.68}, abstractNote={The Azambuja fault is a NNE trending structure located 50 km NE of Lisbon, in an area of important historical seismicity. It is sited in the Lower Tagus Basin, a compressive foredeep basin related to tectonic inversion of the Mesozoic Lusitanian Basin in the Miocene. The fault is evident in commercial seismic reflection data, where it shows steep thrust geometry downthrowing the Cenozoic sediments to the east. It has also a clear morphological signature, presenting a NNE-SSW trending, east facing, 15 km long scarp, reaching a maximum height of 80 m. The fault scarp is the geomorphic appearance of a flexure expressed as a zone of distributed deformation, where Miocene and Pliocene sediments are tilted eastwards and are cut by steeply dipping meso-scale faults presenting reverse and normal offsets, with a net downthrow to the east. This pattern at the surface is compatible with a steep fault in the basement that tilts and branches through the overlying Cenozoic sedimentary cover. In order to constrain the neotectonic activity of this structure, detailed geological studies were conducted. Morphotectonics was studied through aerial photo interpretation, analysis of topographic maps and digital mapping. Those studies indicate Quaternary slip on the fault in the ranges of 0.05–0.06 mm per year. Seismogenic behaviour was assumed for the Azambuja fault based on the evidence of Quaternary tectonic activity and its location in an area of significant historical seismicity. M w 6.4–6.7 maximum earthquakes, with recurrence intervals of 10000–25000 years, were estimated based upon the displaced morphological references, cumulative offsets and fault length.}, number={3}, journal={Journal of Seismology}, author={Cabral, J. and Ribeiro, P. and Figueiredo, P. and Pimentel, N. and Martins, A.}, year={2004}, pages={347–362} } @inproceedings{new data on the active surface faulting vs. landsliding controversy concerning the vila chã de ourique site (lower tagus valley)_2003, booktitle={6th Portuguese Geological Congress}, year={2003} } @article{perea_figueiredo_carner_gambini_boydell_2003, title={Paleoseismological data from a new trench across the El Camp Fault (Catalan Coastal Ranges, NE Iberian Peninsula)}, volume={46}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-2042527665&partnerID=MN8TOARS}, number={5}, journal={Annals of Geophysics}, author={Perea, H. and Figueiredo, P.M. and Carner, J. and Gambini, S. and Boydell, K.}, year={2003}, pages={763–774} } @article{paleoseismological data from a new trench across the el camp fault (catalan coastal ranges, ne iberian peninsula)_2003, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-2042527665&partnerID=MN8TOARS}, journal={Annals of Geophysics}, year={2003} } @inproceedings{paleoseismicity evidence in the lower tagus valley? an example of misinterpretation of geological data_2002, booktitle={3rd Geophysics and Geodesy Port.- Spain Meeting}, year={2002} } @inproceedings{surface evidence of seismogenic activity in the vila franca de xira fault (tagus valley, portugal), _2002, booktitle={XXVIII General Assembly European Seismological Commission}, year={2002} } @inproceedings{europaleos: new data on paleoseismological studies in el camp fault, spain_2001, booktitle={Ten years of paleoseismology in the ILP: progress and prospects}, year={2001} }