Christopher DuRoss

United States Geological Survey | USGS · Geologic Hazards Science Center

Surface rupture in the 2019 Ridgecrest, California, earthquake sequence occurred along two orthogonal cross faults and includes dominantly left-lateral and northeast-striking rupture in the Mw 6.4 foreshock and dominantly right-lateral and northwest-striking rupture in the Mw 7.1 mainshock. We present >650 field-based, surface-displacement observat...

The 72-km-long Teton normal fault bounds the eastern base of the Teton Range in northwestern Wyoming, USA. Although geomorphic surfaces along the fault record latest Pleistocene to Holocene fault movement, the postglacial earthquake history of the fault has remained enigmatic. We excavated a paleoseismic trench at the Buffalo Bowl site along the so...

Bayesian statistical analyses of paleoseismic data result in the probabilistic determination of earthquake times using geochronological data evaluated in the context of a stratigraphic model. However, a fundamental problem in paleoseismology is how to use the Bayesian approach to model sparse and/or conflicting geochronological datasets, such as th...

We investigate a shallow lake basin for evidence of a large historic intraplate earthquake in western North America. Henrys Lake, Idaho is an atypical candidate for lacustrine paleoseismic study given its shallow depth (∼7 m) and low relief (≤2° slopes). Here, we test the earthquake‐recording capacity of this basin type by showing sedimentological...

Field investigations have long been an important component of the scientific response to surface-faulting earthquakes. However, in light of advances in remote data and models, the question arises whether field-based observations of surface rupture remain useful for understanding rupture processes and seismic hazards. We approach this question using...

The last National Seismic Hazard Model (NSHM) for Puerto Rico and the U.S. Virgin Islands (PRVI) was published in 2003. In advance of the 2025 PRVI NSHM update, we created three geologic input databases to summarize new onshore and offshore fault source information in the northern Caribbean region between 62°–70° W and 16°–21° N. These databases, o...

The 2020 moment magnitude (Mw) 6.5 Stanley, Idaho, earthquake raised questions about the history and extent of complex faulting in the northwestern Centennial Tectonic Belt (CTB) and its relation to the Sawtooth normal fault and Eocene Trans-Challis fault system (TCFS). To explore faulting in this area, we excavated a paleoseismic trench across the...

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 for public policy and other engineering applications (defined for return periods greater than ∼475 or less than ∼10,000 years). Changes in 2...

We present the 2023 U.S. Geological Survey time-independent earthquake rupture forecast for the conterminous United States, which gives authoritative estimates of the magnitude, location, and time-averaged frequency of potentially damaging earthquakes throughout the region. In addition to updating virtually all model components, a major focus has b...

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 km) faults. Constraining the length and magnitude of surface displacement on the causative faults is critical for loss estimates, recovery efforts, rapid identification...

USGS Data Release of satellite mapping from the 6 February 2023 earthquakes in southern Türkiye.

The 6 February 2023 Mw 7.8 Pazarcık and subsequent Mw 7.5 Elbistan earthquakes generated strong ground shaking that resulted in catastrophic human and economic loss across south-central Türkiye and northwest Syria. The rapid characterization of the earthquakes, including their location, size, fault geometries, and slip kinematics, is critical to es...

It has been about a decade since updates to seismic and fault sources in the central and eastern United States (CEUS) were last assessed for the 2012 Central and Eastern United States Seismic Source Characterization for nuclear facilities (CEUS-SSCn) and 2014 U.S. Geological Survey National Seismic Hazard Model (NSHM) for the conterminous United St...

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 the western United States: the NSHM23 fault sections database (FSD) and earthquake geology database (EQGeoDB). In prior iterations of NSHM, fault sections were included only if...

Paleoearthquake studies that inform seismic hazard rely on assumptions of sediment transport that remain largely untested. Here, we test a widespread conceptual model and a new numerical model on the formation of colluvial wedges, a key deposit used to constrain the timing of paleoearthquakes. We perform this test by applying luminescence, a sunlig...

Despite its subdued expression and isolated location within the Great Plains of southeastern Colorado, the 80 km long Cheraw fault may be one of the most active faults in North America east of the Rocky Mountains. We present geomorphic analyses, geochronology, and paleoseismic trenching data to (1) document the rupture history of the ∼45 km long so...

The development of colluvial wedges at the base of fault scarps following normal-faulting earthquakes serves as a sedimentary record of paleoearthquakes and is thus crucial in assessing seismic hazard. Although there is a large body of observations of colluvial wedge development, connecting this knowledge to the physics of sediment transport can op...

We excavated trenches at two paleoseismic sites bounding a trans-basin bedrock ridge (the Willow Creek Hills) along the northern Lost River fault zone to explore the uniqueness of the 1983 Mw 6.9 Borah Peak earthquake compared to its prehistoric predecessors. At the Sheep Creek site on the southernmost Warm Springs section, two earthquakes occurred...

The quality and quantity of geochronologic data used to constrain the history of major earthquakes in a region exerts a first-order control on the accuracy of seismic hazard assessments that affect millions of people. However, evaluations of geochronological data are limited by uncertainties related to inherently complex depositional processes that...

The development of colluvial wedges at the base of fault scarps following normal-faulting earthquakes serves as a sedimentary record of paleoearthquakes and is thus crucial in assessing seismic hazard. Although there is a large body of observations of colluvial wedge development, connecting this knowledge to the physics of sediment transport can op...

A new history of great earthquakes (and their tsunamis) for the central and southern Cascadia subduction zone shows more frequent (17 in the past 6700 yr) megathrust ruptures than previous coastal chronologies. The history is based on along-strike correlations of Bayesian age models derived from evaluation of 554 radiocarbon ages that date earthqua...

Structure-from-motion (SfM) modeling has dramatically increased the speed of generating geometrically accurate orthophoto mosaics of paleoseismic trenches, but some aspects of this technique remain time and labor intensive. Model accuracy relies on control points to establish scale, reduce distortion, and orient 3D models. Traditional SfM methods u...

Active traces of the southern Fairweather fault were revealed by light detection and ranging (lidar) and show evidence for transpressional deformation between North America and the Yakutat block in southeast Alaska. We map the Holocene geomorphic expression of tectonic deformation along the southern 30 km of the Fairweather fault, which ruptured in...

How structural segment boundaries modulate earthquake behavior is an important scientific and societal question, especially for the Wasatch fault zone (WFZ) where urban areas lie along multiple fault segments. The extent to which segment boundaries arrest ruptures, host moderate magnitude earthquakes, or transmit ruptures to adjacent fault segments...

A fundamental topic in earthquake studies is understanding the extent to which fault rupture at the surface is localized on primary fault strands as opposed to distributed tens to hundreds of meters away from primary ruptures through off-fault deformation (OFD) via a combination of discrete secondary faulting and bulk deformation. The 2019 Ridgecre...

The 72-km-long Teton fault in northwestern Wyoming is an ideal candidate for reconstructing the lateral extent of surface-rupturing earthquakes and testing models of normal-fault segmentation. To explore the history of earthquakes on the northern Teton fault, we hand excavated two trenches at the Steamboat Mountain site, where the east-dipping Teto...

Shallowly dipping (<30°) low‐angle normal faults (LANFs) have been documented globally; however, examples of active LANFs in continental settings are limited. The western margin of the Panamint Range in eastern California is defined by a LANF that dips west beneath Panamint Valley and has evidence of Quaternary motion. In addition, high‐angle dextr...

Plain Language Summary On 18 March 2020, a moment magnitude (Mw) 5.7 earthquake occurred beneath Magna, Utah, a suburb of Salt Lake City. It was the largest earthquake in the Wasatch fault system in historical times, and shaking was felt throughout northern Utah. The mainshock and its aftershocks were located in the middle of a dense seismic networ...

The Mw 6.4 and Mw 7.1 Ridgecrest earthquake sequence occurred on 4 and 5 July 2019 within the eastern California shear zone of southern California. Both events produced extensive surface faulting and ground deformation within Indian Wells Valley and Searles Valley. In the weeks following the earthquakes, more than six dozen scientists from governme...

The July 2019 Ridgecrest earthquakes in southeastern California were characterized as surprising by some, because only ∼35% of the rupture occurred on previously mapped faults. Employing more detailed inspection of pre-event high-resolution topography and imagery in combination with field observations, we document evidence of active faulting in the...

The multisegment Wasatch fault zone is a well‐studied normal fault in the western United States that has paleoseismic evidence of recurrent Holocene surface‐faulting earthquakes. Along the 270 km long central part of the fault, four primary structural complexities provide possible along‐strike limits to these ruptures and form the basis for models...

Prominent scarps on Pinedale glacial surfaces along the eastern base of the Teton Range confirm latest Pleistocene to Holocene surface‐faulting earthquakes on the Teton fault, but the timing of these events is only broadly constrained by a single previous paleoseismic study. We excavated two trenches at the Leigh Lake site near the center of the Te...

The 1983 Mw 6.9 Borah Peak earthquake generated ~36 km of surface rupture along the Thousand Springs and Warm Springs sections of the Lost River fault zone (LRFZ, Idaho, USA). Although the rupture is a well-studied example of multisegment surface faulting, ambiguity remains regarding the degree to which a bedrock ridge and branch fault at the Willo...

This document accompanies a high-resolution topographic data set and orthomosaics of part of the Lost River fault zone (LFRZ), Idaho, USA. The topographic data set covers the northern ~16 km of the surface-rupture that occurred on the LRFZ in the Mw 6.9 1983 Borah Peak Earthquake (Figure 1). Point clouds and digital surface models (DSMs), were gene...

Static and quasi-static Coulomb stress changes produced by large earthquakes can modify the probability of occurrence of subsequent events on neighboring faults. This approach is based on physical (Coulomb stress changes) and statistical (probability calculations) models, which are influenced by the quality and quantity of data available in the stu...

This report provides trench photomosaics, logs and related site information, age data, and earthquake event evidence from three paleoseismic trench sites on the Bear River Fault Zone. Our motivation for studying the Bear River Fault Zone - a nascent normal fault in the Rocky Mountains east of the Basin and Range physiographic province - is twofold:...

Static and quasi-static Coulomb stress changes produced by large earthquakes can modify the probability of occurrence of subsequent events on neighboring faults. This approach is based on physical (Coulomb stress changes) and statistical (probability calculations) models, which are influenced by the quality and quantity of data available in the stu...

Three sequences of well‐documented, major ~M7+ earthquakes (1811–1812, ~1450, and ~900 CE) in the New Madrid seismic zone, USA, contribute significantly to seismic hazard in the region. However, it is unknown whether this <550‐year recurrence interval has been constant throughout the Holocene given limited geomorphic evidence of prior earthquakes....

The Cheraw fault is one of the few faults east of the Rocky Mountains with evidence of Quaternary surface rupture that is considered in regional seismic hazard models of the central and eastern United States. The prior record of large earthquakes on the Cheraw fault includes three events from ~22 to ~8 ka interpreted by Crone et al. (1997; USGS Map...

To improve the characterization of Holocene earthquakes on the Wasatch fault zone (WFZ), we conducted light detection and ranging (lidar)-based neotectonic mapping and excavated a paleoseismic trench across an 8-m-high fault scarp near Alpine, Utah, located < 1 km south of the boundary between the Salt Lake City and Provo segments (SLCS and PS). We...

The Teton fault is the major range bounding normal fault along the eastern flank of the Teton Range in western Wyoming and a significant contributor to regional seismic hazard. The ~70 km-long fault has an estimated vertical slip rate of ~1-2 mm/yr; however, the history of large earthquakes on the fault remains uncertain because paleoseismic data a...

The Teton normal fault runs along the eastern base of the prominent Teton range for ~70 km and defines the northeastern margin of the Basin and Range extensional province (Wyoming, USA). The fault has a latest Pleistocene vertical slip rate of ~1-2 mm/yr as indicated by faulted Pinedale glacial surfaces. However, a paleoseismic record of two surfac...

Faulted terrace risers are semi-planar features commonly used to constrain Quaternary slip rates along strike-slip faults. These landforms are difficult to date directly and therefore their ages are commonly bracketed by age estimates of the adjacent upper and lower terrace surfaces. However, substantial differences in the ages of the upper and low...

The 1934 Ms 6.6 Hansel Valley, Utah, earthquake produced an 8-km-long by 3-km wide zone of north-south–trending surface deformation in an extensional basin within the easternmost Basin and Range Province. Less than 0.5 m of purely vertical displacement was measured at the surface, although seismologic data suggest mostly strike-slip faulting at dep...

The 1934 Ms 6.6 Hansel Valley, Utah earthquake produced an 8-km-long by 3-km-wide zone of north-south trending surface deformation in an extensional basin within the easternmost Basin and Range province. Less than 0.5 m of only vertical displacement was measured at the surface, although seismologic data suggest mostly strike-slip faulting at depth....

The Cheraw fault (CF) is one of the few Quaternary-active faults expressed at the surface in the Central and Eastern U.S. Our recent investigations of the CF have expanded evidence of Quaternary surface deformation and verified the connection between surface scarps and basement structure. To address uncertainties in the fault's late Quaternary slip...

The Fort Canyon fault (FCF) trends east-west across Traverse Ridge, linking the Salt Lake City and Provo segments of the Wasatch fault, which dips directly beneath the densely-populated Salt Lake-Provo metropolitan area. Understanding the history of surface-rupturing earthquakes on the FCF is important because the extent to which segment boundary f...

The Teton fault is the major range bounding normal fault along the eastern flank of the Teton Range in western Wyoming. The 72 km-long fault has an estimated slip rate of 0.7 to 1.3 mm/yr and is the major contributor to regional seismic hazard. However, uncertainty in the history of large earthquakes on the fault remains because previous paleoseism...

In the first comprehensive study of its kind in the Intermountain West, the Working Group on Utah Earthquake Probabilities (WGUEP, 2016) has assessed the likelihood of large earthquakes in the Wasatch Front region. This forecast conveys the probability of one or more earthquakes of a specified magnitude range in the region in the next 50 and 100 ye...

To improve characterization of Holocene earthquakes on the Wasatch fault zone (WFZ), we excavated a paleoseismic trench and performed a ground-penetrating radar (GPR) survey across an 8 m-high fault scarp near Alpine, Utah, located <1 km south of the boundary between the Salt Lake City and Provo segments (SLCS, PS). We document evidence for six pal...

Prominent structural discontinuities along normal fault systems such as the Wasatch fault zone (WFZ) are thought to play an important role in limiting the lateral extent of individual surface-rupturing earthquakes. To test this assumption, we evaluated the history of large earthquakes at the Corner Canyon site on the Salt Lake City segment (SLCS) o...

The Wasatch fault (WFZ)—Utah’s longest and most active normal fault—forms a prominent eastern boundary to the Basin and Range Province in northern Utah. To provide paleoseismic data for a Wasatch Front regional earthquake forecast, we synthesized paleoseismic data to define the timing and displacements of late Holocene surface-faulting earthquakes...

The Nephi segment of the Wasatch fault zone (WFZ) comprises two fault strands, the northern and southern strands, which have evidence of recurrent late Holocene surface-faulting earthquakes. We excavated paleoseismic trenches across these strands to refine and expand their Holocene earthquake chronologies; improve estimates of earthquake recurrence...

To improve knowledge of the Teton fault’s ground-rupturing earthquake history, we excavated trenches across two fault scarps near the southwest shore of Leigh Lake. Detailed stratigraphic and sedimentologic analyses allow preliminary inferences regarding the fault history. The trenches exposed faulted glacial sediments and overlying hillslope collu...