A5031121693- earthquake and tectonic studies
- Geological and Geochemical Analysis
- Seismology and Earthquake Studies
- Geology and Paleoclimatology Research
- Earthquake Detection and Analysis
- Seismic Waves and Analysis
- High-pressure geophysics and materials
- Landslides and related hazards
- Seismic Performance and Analysis
- Geological Modeling and Analysis
- Earthquake and Tsunami Effects
- Seismic Imaging and Inversion Techniques
- Tree-ring climate responses
- Distributed and Parallel Computing Systems
- Hydraulic Fracturing and Reservoir Analysis
- Rock Mechanics and Modeling
- Simulation Techniques and Applications
- Earthquake and Disaster Impact Studies
- Water Quality and Resources Studies
- Geological formations and processes
- Geological and Geophysical Studies Worldwide
- Structural Response to Dynamic Loads
- Botany and Geology in Latin America and Caribbean
- Drilling and Well Engineering
- Geochemistry and Geologic Mapping
United States Geological Survey
2020-2024
Geologic Hazards Science Center
2021-2024
University of Southern California
2015-2023
Denver Federal Center
2023
Southern California Earthquake Center
2018-2020
University of Massachusetts Amherst
2015-2017
Southern California University for Professional Studies
2015
Abstract The 6 February 2023 Mw 7.8 Pazarcık and subsequent 7.5 Elbistan earthquakes generated strong ground shaking that resulted in catastrophic human economic loss across south-central Türkiye northwest Syria. rapid characterization of the earthquakes, including their location, size, fault geometries, slip kinematics, is critical to estimate impact significant seismic events. U.S. Geological Survey National Earthquake Information Center (NEIC) provides real-time monitoring globally,...
The US National Seismic Hazard Model (NSHM) was updated in 2023 for all 50 states using new science on seismicity, fault ruptures, ground motions, and probabilistic techniques to produce a standard of practice public policy other engineering applications (defined return periods greater than ∼475 or less ∼10,000 years). Changes time-independent seismic hazard (both increases decreases compared previous NSHMs) are substantial because the model considers more data earthquake rupture forecasts...
Research Article| June 12, 2018 Surface Rupture of Multiple Crustal Faults in the 2016 Mw 7.8 Kaikōura, New Zealand, Earthquake Nicola J. Litchfield; Litchfield aGNS Science, P.O. Box 30‐368, Lower Hutt 5040, n.litchfield@gns.cri.nz Search for other works by this author on: GSW Google Scholar Pilar Villamor; Villamor Russ Van Dissen; Dissen Andrew Nicol; Nicol bUniversity Canterbury, Private Bag 4800, Christchurch 8140, Zealand Philip M. Barnes; Barnes cNational Institute Water and...
ABSTRACT Surface rupture in the 2019 Ridgecrest, California, earthquake sequence occurred along two orthogonal cross faults and includes dominantly left-lateral northeast-striking Mw 6.4 foreshock right-lateral northwest-striking 7.1 mainshock. We present >650 field-based, surface-displacement observations for these ruptures synthesize our results into cumulative along-strike displacement distributions. Using data, we calculate gradients compare with historical strike-slip eastern...
ABSTRACT We present the 2023 U.S. Geological Survey time-independent earthquake rupture forecast for conterminous United States, which gives authoritative estimates of magnitude, location, and time-averaged frequency potentially damaging earthquakes throughout region. In addition to updating virtually all model components, a major focus has been provide better representation epistemic uncertainties. For example, we have improved multifault ruptures, both in terms allowing more less fault...
Abstract The 6 February 2023 Kahramanmaraş, Turkey (Türkiye), earthquake sequence produced > 500 km of surface rupture primarily on the left-lateral East Anatolian (~345 km) and Çardak (~175 faults. Constraining length magnitude displacement causative faults is critical for loss estimates, recovery efforts, rapid identification impacted infrastructure, fault hazard analysis. To support these we rapidly mapped from satellite data with remote sensing field teams, released results to...
Abstract The Mw 6.4 and 7.1 Ridgecrest earthquake sequence occurred on 4 5 July 2019 within the eastern California shear zone of southern California. Both events produced extensive surface faulting ground deformation Indian Wells Valley Searles Valley. In weeks following earthquakes, more than six dozen scientists from government, academia, private sector carefully documented ground-deformation features. As December 2019, we have compiled a total 6000 observations; approximately 1500 these...
Abstract The M 6.5 Monte Cristo Range earthquake that occurred in the central Walker Lane on 15 May 2020 was largest Nevada 66 yr and resulted a multidisciplinary scientific field response. result of left-lateral slip along largely unmapped parts Candelaria fault, one series east–northeast-striking faults comprise Mina deflection, major right step north–northwest structural grain Lane. We describe characteristics surface rupture document distinct differences style orientation fractures...
Abstract The U.S. Geological Survey (USGS) National Earthquake Information Center (NEIC) estimates source characteristics of significant damaging earthquakes, aiming to place events within their seismotectonic framework. Contextualizing the 8 September 2023, Mw 6.8 Al Haouz, Morocco, earthquake is challenging, because it occurred in an enigmatic region active surface faulting, and low seismicity yet produced damage loss life. Here, we present rapid products by USGS NEIC, describing how model...
Abstract Fault geometry and slip rates are key input data for geologic deformation models, which a fundamental component of probabilistic seismic hazard analyses (PSHAs). However, sources PSHA have traditionally been limited to faults with field-based rate constraints, results in underrepresentation known, but partially characterized, active faults. Here, we evaluate fault geometries the western United States construct new model U.S. National Seismic Hazard Model 2023 update (NSHM23). In...
Research Article| June 12, 2018 Coseismic Rupture and Preliminary Slip Estimates for the Papatea Fault Its Role in 2016 Mw 7.8 Kaikōura, New Zealand, Earthquake Robert M. Langridge; Langridge aGNS Science, P.O. Box 30‐368, Lower Hutt 5040, R.Langridge@gns.cri.nz Search other works by this author on: GSW Google Scholar Julie Rowland; Rowland bThe University of Auckland, Private Bag 92019, Auckland 1142, Zealand Pilar Villamor; Villamor Joshu Mountjoy; Mountjoy cNational Institute Water...
As part of the U.S. National Seismic Hazard Model (NSHM) update planned for 2023, two databases were prepared to more completely represent Quaternary-active faulting across western United States: NSHM23 fault sections database (FSD) and earthquake geology (EQGeoDB). In prior iterations NSHM, included only if a field-measurement-derived slip rate was estimated along given fault. By expanding this inclusion criteria, we able assess larger set faults use in NSHM23. The USGS Quaternary Fault...
Abstract This report describes geodetic and geologic information used to constrain deformation models of the 2023 update National Seismic Hazard Model (NSHM), a set interpret these data, their implications for earthquake rates in western United States. Recent updates provide much larger data Global Positioning System crustal velocities than 2014 NSHM, as well hundreds new faults considered active sources NSHM. These are interpreted by four that estimate fault slip uncertainties together with...
Abstract Restraining bends along strike‐slip fault systems evolve by both propagation of new faults and abandonment segments. Scaled analog modeling using wet kaolin allows for qualitative quantitative observations this evolution. To explore how bend geometry affects evolution, we model with a variety initial angles, θ , from = 0° straight to 30°. High‐angle restraining ( ≥ 20°) overcome inefficiencies abandoning unfavorably oriented segments propagating multiple new, inwardly dipping,...
Abstract Incremental slip rates of the Clarence fault, a dextral fault in Marlborough system South Island, New Zealand, varied by factor 4–5 during Holocene–latest Pleistocene time, as revealed geomorphic mapping and luminescence dating faulted fluvial landforms at Tophouse Road site. We used high‐resolution lidar microtopographic data field surveys to map fine‐scale geomorphology precisely restore offset features. dated offsets using stratigraphically informed protocol for infrared...
Abstract As part of the U.S. Geological Survey’s 2023 50-State National Seismic Hazard Model (NSHM), we make modest revisions and additions to central eastern (CEUS) fault-based seismic source model that result in locally substantial hazard changes. The CEUS was last updated as 2014 NSHM considered new information from Source Characterization for Nuclear Facilities (CEUS-SSCn) Project. Since then, geologic investigations have led revised fault fault-zone inputs, release databases sources...
Abstract The last National Seismic Hazard Model (NSHM) for Puerto Rico and the U.S. Virgin Islands (PRVI) was published in 2003. In advance of 2025 PRVI NSHM update, we created three geologic input databases to summarize new onshore offshore fault source information northern Caribbean region between 62°–70° W 16°–21° N. These databases, sections, fault-zone polygons, estimates activity (fault-slip rate earthquake recurrence intervals) at specific sites, document updates parameters used prior...
Abstract It has been about a decade since updates to seismic and fault sources in the central eastern United States (CEUS) were last assessed for 2012 Central Eastern Seismic Source Characterization nuclear facilities (CEUS-SSCn) 2014 U.S. Geological Survey National Hazard Model (NSHM) conterminous States. In advance of 2023 NSHM update, we created three related geospatial databases summarize characterize new source information CEUS. These include section, fault-zone polygon, earthquake...
Abstract We develop a model for the evolution and activity of Garlock fault that combines elements three previously proposed mechanisms: (1) conjugate slip to San Andreas fault, (2) extension in Basin Range, (3) bending from oblique shear eastern California zone (ECSZ). Conjugate is greatest west decreases eastward. Conversely, extension‐induced increases westward termination reaching maximum at intersection with Sierra Nevada frontal fault. Oroclinal provides only small contribution...
Abstract We use high‐resolution lidar microtopographic data and luminescence dating to constrain incremental Holocene–latest Pleistocene slip rates for the Wairau fault, a major dextral strike‐slip fault in Marlborough Fault System, South Island, New Zealand. Our come from two closely spaced study areas along structurally simple, central portion of fault: The well‐known Branch River terrace flight, previously undated series offset risers channel features several km east that we refer as...
Research Article| November 01, 2015 Evolution and progressive geomorphic manifestation of surface faulting: A comparison the Wairau Awatere faults, South Island, New Zealand Robert Zinke; Zinke 1Department Earth Sciences, University Southern California, Los Angeles, California 90089, USA Search for other works by this author on: GSW Google Scholar James F. Dolan; Dolan Russell Van Dissen; Dissen 2GNS Science, PO Box 30-368, Lower Hutt, Jessica R. Grenader; Grenader Edward J. Rhodes; Rhodes...
Abstract Paleoseismic trenches excavated at two sites reveal ages of late Holocene earthquakes along the Conway segment Hope fault, fastest-slipping fault within Marlborough system in northern South Island, New Zealand. At Green Burn East (GBE) site, a fault-perpendicular trench exposed gravel colluvial wedges, fissure fills, and upward terminations associated with five paleo-surface ruptures. Radiocarbon age constraints indicate that these occurred after 36 B.C.E., four most recent surface...
Abstract Geomorphic field and aerial lidar mapping, coupled with fault-parallel trenching, reveals four progressive offsets of a stream channel an older offset the headwaters associated fill terrace–bedrock contact at Hossack Station along Conway segment Hope fault, fastest-slipping fault within Marlborough system in northern South Island, New Zealand. Radiocarbon luminescence dating aggradational surface deposition initiation abandonment event horizons yields not only average dextral rate...