Eric S. Cowgill

• University of California, Davis

Back‐arc basins frequently form within subduction zones, creating sources of lithospheric weakness that can accommodate subsequent compressional deformation. The crustal structure of these basins, including whether they contain extended preexisting crust and/or new crust formed by seafloor spreading, can thus exert a major influence on strain parti...

Fault slip histories are essential for understanding seismic hazard and regional fault system development but fundamentally depend on identifying, dating, and reconstructing displaced markers. Here, we use a case study of the Pearblossom site along the Mojave section of the San Andreas fault in California (USA) to show how pulses of sediment aggrad...

Because the active, left‐slip Haiyuan fault is a first‐order structure along the NE margin of the Tibetan Plateau, its tectonic evolution provides insight into deformation processes along this margin over time. Late Cenozoic deformation in the area of the eastern Haiyuan fault initiated as thrust faulting, followed by left‐lateral strike slip displ...

Although many collisional orogens form after subduction of oceanic lithosphere between two continents, some orogens result from strain localization within a continent via inversion of structures inherited from continental rifting. Intracontinental rift-inversion orogens exhibit a range of structural styles, but the underlying causes of such variabi...

Our objective is to improve the view of the seismicity in the Caucasus region using instrumental data between 1951 and 2019. To create a comprehensive catalog, we combine the bulletins of local agencies and the International Seismological Centre, and use an advanced single-event location algorithm, iLoc, to obtain better locations. We show that rel...

With an obliquity of ∼30° relative to plate motion direction, the ∼300‐km‐long Big Bend of the San Andreas Fault is one of the world's largest restraining bends. The 5–6 Ma (∼160 km of total displacement) longevity of this mechanically inefficient structure and the lack of evidence for associated widespread uplift both challenge existing models of...

To determine the post‐40 ka slip‐rate along the Mojave section of the San Andreas Fault (MSAF) we re‐analyze the sedimentary record preserved where Little Rock (LR) Creek flows across the fault. At this location, interaction between the northeast‐flowing stream and right‐lateral fault has resulted in the abandonment and preservation of 11 strath te...

Convergent margins play a fundamental role in the construction and modification of Earth's lithosphere and are characterized by poorly understood episodic processes that occur during the progression from subduction to terminal collision. On the northern margin of the active Arabia‐Eurasia collision zone, the Greater Caucasus Mountains provide an op...

Although many collisional orogens result from subduction of oceanic lithosphere between two continents, some orogens form by strain localization within a continent via inversion of extensional structures inherited during continental rifting. Intracontinental rift-inversion orogens exhibit a wide range of first-order structural styles, but the under...

The west-northwest trending Greater Caucasus (GC) mountains locally represent the main locus of post-Pliocene shortening within the north central Arabia-Eurasia collision. Although recent low-temperature thermochronology constrains the timing of orogen formation, the evolution of major structures remains enigmatic - particularly regarding the inter...

The Greater Caucasus orogen forms the northern edge of the Arabia-Eurasia collision zone. Although the orogen has long been assumed to exhibit dominantly thick-skinned style deformation via reactivation of high-angle extensional faults, recent work suggests the range may have accommodated several hundred kilometers or more of shortening since its ~...

Fault characterization is a critical step toward improving seismic hazard assessment in the Georgian Greater Caucasus but is largely absent from the region. Here, a paleoseismic trench near the capital city of Tbilisi revealed evidence for recurring surface rupture on a shallowly north-dipping thrust fault. The fault has broken through the overturn...

The geologic slip rate on the Mojave section of the San Andreas fault is poorly constrained, despite its importance for understanding earthquake hazard, apparent discrepancies between geologic and geodetic slip rates along this fault section, and long-term fault interactions in southern California. Here, we use surficial geologic mapping, excavatio...

Although the Greater Caucasus Mountains have played a central role in absorbing late Cenozoic convergence between the Arabian and Eurasian plates, the orogenic architecture and the ways in which it accommodates modern shortening remain debated. Here, we addressed this problem using geologic mapping along two transects across the southern half of th...

Although the Greater Caucasus (GC) Mountains accommodate a significant fraction of orogen-perpendicular Arabia-Eurasia convergence at their longitude, the locations and slip rates of the active structures absorbing this shortening are poorly known. Here we report the first late Quaternary shortening rate for an active thrust in the GC determined fr...

The Caucasus has a documented history of cataloging earthquakes stretching back to the beginning of the Christian era. Instrumental seismic observation in the Caucasus began in 1899, when the first seismograph was installed in Tbilisi, Georgia. During the Soviet era (1921–1991 in Georgia), the number of seismic stations increased in the region, pro...

Along the northern margin of the Arabia‐Eurasia collision zone in the western Greater Caucasus, the Main Caucasus Thrust (MCT) juxtaposes Paleozoic crystalline basement to the north against Mesozoic metasedimentary and volcaniclastic rocks to the south. The MCT is commonly assumed to be the trace of an active plate‐boundary scale structure that acc...

Earthquake recurrence models assume that major surface-rupturing earthquakes are followed by periods of reduced rupture probability as stress rebuilds. Although purely periodic, time- or slip-predictable rupture models are known to be oversimplifications, a paucity of long records of fault slip clouds understanding of fault behavior and earthquake...

The Greater Caucasus Mountains are a young (~5 m.y. old) orogen within the Arabia-Eurasia collision zone that contains the highest peaks in Europe and has an unusual topographic form for a doubly vergent orogen. In the east-central part (45°E–49°E), the range is nearly symmetric in terms of prowedge and retrowedge widths and the drainage divide is...

The Greater Caucasus Mountains, due to their youth (~5 Ma), provide an opportunity for insight into the early stages of orogen development during continent-continent collision. However, their recent tectonic evolution and first-order architecture remain unclear. Here we investigate the evolution of the orogen by integrating new observations of the...

An assessment of hydro project-related geohazards (AHPRG) has, as its salient features, vast assessed project areas, timeliness, complex objects and contents, lack of large scale geologic maps and poor traffic conditions. Unfavorable factors often hinder engineering geologists arriving at geologic disaster sites successfully and in time. With the d...

Relative ages of late Cenozoic stratigraphy throughout the Caspian region are referenced to regional stages that are defined by changes in microfauna and associated extreme (>1000 meter) variations in Caspian base level. However, the absolute ages of these stage boundaries may be significantly diachronous because many are based on the first occurre...

The earthquake behavior of intra-continental strike-slip faults is poorly understood, particularly where actively deforming areas lie adjacent to stable regions. Strain concentration on these structures is capable of producing severe earthquakes, but what is the longest rupture (i.e. biggest earthquake) possible on a continental strike-slip fault?...

The Caspian Sea is characterized by significant variations in its base level during the late Cenozoic and provides an important repository for long-term records of both regional climate and tectonics due to its position within the interior of the Eurasian continent and at the northern margin of the ongoing Arabia-Eurasia collision zone. The Caspian...

[1] The Greater Caucasus are the northernmost extent of the Arabia-Eurasia collision and are thought to represent the main locus of shortening within the central portion of the collision zone between 40° and 48°E. Recent work suggests that in detail, since the Plio-Pleistocene, much of the shortening in the eastern portion of the Caucasus system ha...

As an alternative to grid-based approaches, point-based computing offers access to the full information stored in unstructured point clouds derived from lidar scans of terrain. By employing appropriate hierarchical data structures and algorithms for out-of-core processing and view-dependent rendering, it is feasible to visualize and analyze three-d...

The geomorphology along active fault zones develops as a balance between the tectonic processes displacing the surface and rocks and the surface processes sculpting the resulting relief. Strike-slip fault zones are well known for their clear manifestation of localized slip along straight sections and distributed deformation and associated increased...

Planetary topography is the result of complex interactions between geological processes, of which faulting is a prominent component. Surface-rupturing earthquakes cut and move landforms which develop across active faults, producing characteristic surface displacements across the fault. Geometric models of faults and their associated surface displac...

The moment magnitude (M-w) 7.0 12 January 2010 Haiti earthquake is the first major earthquake for which a large-footprint LiDAR (light detection and ranging) survey was acquired within several weeks of the event. Here, we describe the use of virtual reality data visualization to analyze massive amounts (67 GB on disk) of multiresolution terrain dat...

Three-dimensional (3D) slip vectors recorded by displaced landforms are difficult to constrain across complex fault zones and the uncertainties associated with such measurements become increasingly challenging to assess as landforms degrade over time. We approach this problem from a remote sensing perspective by using terrestrial laser scanning (TL...

Marine terraces are landforms that record both paleohorizontal and true surface uplift above mean sea level, and thus serve as long-baseline geodetic markers. Here we present a method for extending terrace records back in time by analyzing 2003 National Aeronautics and Space Administration (NASA) airborne LiDAR data to discover a suite of probable...

The west-northwest trending Greater Caucasus Mountains form the northern margin of the Arabia-Eurasia collision between 40° and 50°E and appear to represent the main locus of shortening since the early Pliocene in this central part of the collision. Compared to similar mountain ranges, few detailed cross sections exist that extend across the whole...

We assess the slip distribution at four sites along the 4 April 2010 El Mayor-Cucapah (EMC) earthquake surface rupture in northern Baja-California with cm-resolution terrestrial lidar (TLS). Slip distributions based on field measurements typically show abrupt variation (0.5-2 m) over short along-strike distances (10 to 100 m), implying large along-...

T. Compton, E. Cowgill, R. Westerteiger, T.S. Bernardin. Measuring histories of fault slip spanning multiple (10-100) ruptures has the potential to advance understanding of fault and fault-system behavior, including temporal variations in the rate of strain release. A kinematic model of interacting fault systems in southern California[1] and long p...

The active, left-lateral Altyn Tagh fault defines the northwestern margin of the Tibetan Plateau in western China. To clarify late Quaternary temporal and spatial variations in slip rate along the central portion of this fault system (85°-90°E), we have more than doubled the number of dated offset markers along the central Altyn Tagh fault. In part...

Virtual globes are becoming ubiquitous in the visualization of planetary bodies and Earth specifically. While many of the current virtual globes have proven to be quite useful for remote geologic investigation, they were never designed for the purpose of serving as virtual geologic instruments. Their shortcomings have become more obvious as earth s...

Although offset and age data from displaced landforms are essential for identifying earthquake clusters and thus testing whether faults slip at uniform or secularly varying rates, it is not clear how the uncertainties in such measurements should be propagated so as to yield a robust fault-slip history (i.e., record of fault displacement over time)....

The Mw 7.0 January 12, 2010 Haiti earthquake ended 240 years of relative quiescence following earthquakes that destroyed Port-au-Prince in 1751 and 1770. We place the 2010 rupture in the context of past earthquakes and future hazards by using remote analysis of airborne LiDAR to observe the topographic expression of active faulting and develop a ne...

The left-lateral Altyn Tagh Fault (ATF) defines the northwestern margin of the Tibetan Plateau, NW China, and is one of several first-order active strike-slip faults within the Indo-Asian orogen. Recent morphochronologic measurements document displacement-age relationships for 12 latest Quaternary faulted geomorphic markers at 6 sites spanning 320...

Faults show temporal variations in slip rate at time scales ranging from the hours following a major rupture to the millions of years over which plate boundaries reorganize. One such behavior is secular variation in slip (SVS), which we define as a pulse of accelerated strain release along a single fault that occurs at a frequency that is > 1 order...

We report newly available data sets and preliminary analysis of ground- and airborne-lidar surveys of the 4 April 2010 El Mayor-Cucapah earthquake rupture. The hyperarid setting and varied surficial geology of this complex rupture zone presents an ideal setting to advance the use of lidar in post-earthquake scientific response. Terrestrial lidar su...

Although the Greater Caucasus forms the northern edge of the Arabia-Eurasia collision, the main locus of shortening has shifted south since 5 Ma, producing the Kura fold-thrust belt in Georgia and Azerbaijan. Eastward-decreasing structural complexity and depth of exposure within the thrust belt suggest eastward propagation of faulting. Two topograp...

High-resolution terrestrial LiDAR (t-LiDAR) datasets collected 12-18 days after the 4 April 2010, Mw7.2 El Mayor-Cucapah earthquake in northern Mexico demonstrate the capability of t-LiDAR to rapidly quantify and preserve details of coseismic surface deformation at high resolution. Though the quantity of equipment required even for highly portable...

Virtual globes are becoming ubiquitous for visualizing the Earth and other planets. However, as earth scientists pursue methods to visually explore and interpret earth surface processes using sub-meter pixel resolution digital elevation models (DEM) and imagery data spanning large areas, limitations of the commonly used virtual globes have emerged....

Measurements derived from high-resolution terrestrial LiDAR (t-Lidar) surveys of landforms displaced during the 16 December 1954 Mw 6.8 Dixie Valley earthquake in central Nevada confirm the absence of historical strike slip north of latitude 39.5°N. This conclusion has implications for the effect of stress changes on the spatial and temporal evolut...

The significant earthquakes of 2010 produced surficial expressions ranging from blind faulting and coastal uplift in Leogane, Haiti and Maule, Chile to surface faulting in Baja California, Mexico and Yushu, China. In Haiti and Baja California geodetic imaging methods strongly guided field reconnaissance and surface rupture mapping efforts, yet in q...

We present a user-assisted approach to extracting and visualizing structural features from point clouds obtained by terrestrial and airborne laser scanning devices. We apply a multi-scale approach to express the membership of local point environments to corresponding geometric shape classes in terms of probability. This information is filtered and...

Although the geometry and kinematics of the first-order structures accommodating Arabia-Eurasia convergence are relatively well known in Turkey and Iran, major shortening structures remain poorly understood within the central portion of the collision zone, in eastern Anatolia and the Caucasus. New remotely sensed neotectonic mapping, synthesis of r...

The Pamir salient defi nes the western end of the Himalayan-Tibetan orogen and has overthrust the Tarim-Tajik basin to the north by ~300 km along a late Cenozoic, south-dipping intracontinental subduction zone. Field mapping, structural measurements, and analysis of mesoscale structures along a 32-km-long reach of the Yarkand River document the tec...

The ongoing Arabian-Eurasian collision provides an opportunity to understand strain localization within a nascent orogen. The central third of this collision lies between the Black and Caspian Seas, with late Cenozic deformation extending over 700 km across strike, from the Zagros in the south to the Greater Caucasus (GC) in the north. The GC range...

Virtual globes have become indispensable tools for visualizing, understanding and presenting data from Earth and other planetary bodies. The scientific community has invested much effort into exploiting existing globes to their fullest potential by refining and adapting their capabilities to better satisfy specific needs. For example, Google Earth...

The W-NW trending Greater Caucasus Mountains form the northern edge of the Arabia-Eurasia collision and accommodate much of the NW-SE convergence, but the evolution of this first-order structural system remains enigmatic. Thermochronologic work suggests that the Greater Caucasus initiated in the W and that uplift propagated E overtime. Since 5 Ma,...

The active, left-lateral Altyn Tagh Fault (ATF) defines the northwestern margin of the Tibetan Plateau (NW China) and is one of several first order strike-slip faults within the Indo-Asian orogen. Based on its length (>1200 km), total offset (360-475 km), initiation age (ca 49 Ma), and depth (~100 km), the ATF is one of the most important single st...

Ground-based LiDAR (Light Detection and Ranging) survey techniques are enabling remote visualization and quantitative analysis of geologic features at unprecedented levels of detail. For example, digital terrain models computed from LiDAR data have been used to measure displaced landforms along active faults and to quantify fault-surface roughness....

For more than two decades the slip rate along the active, left-slip Altyn Tagh fault of northwestern Tibet has been disputed, with millennial rates reported to be as much as three times faster than those determined geodetically. This problem is significant because the total offset, plate-boundary length, and age of the Altyn Tagh fault make it the...

At late Quaternary timescales, offset fluvial terrace risers are among the most common landforms used to determine rates of strike-slip faulting. Although diachroneity in the age of riser segments on opposite sides of the fault has been noted previously, an unexplored source of uncertainty associated with deriving slip rates from these markers cent...

Closure of Neotethys during the Arabia-Eurasia collision has produced a wide belt of deformation in the southern foreland of the Greater Caucasus. Since 5 Ma, the main locus of shortening has shifted from within the Greater Caucasus southward to the Kura fold-thrust belt in Georgia and Azerbaijan. This belt is characterized by an eastward decrease...

Airborne and tripod-based LiDaR scans are capable of producing new insight into geologic features by providing high-quality 3D measurements of the landscape. High-resolution LiDaR is a promising method for studying slip on faults, erosion, and other landscape-altering processes. LiDaR scans can produce up to several billion individual point returns...

High resolution topographic measurements form the basis for slip-rate studies along active fault systems. However, meter-scale features such as fault scarps or offset terrace risers are insufficiently resolved on available remotely-sensed digital elevation models (e.g., 10 m NED), rendering it necessary to make field- based topographic measurements...

In the central Arabia-Eurasia collision, closure of Neotethys has produced the WNW-trending Kura fold-thrust belt, which is separated from the Greater Caucasus to the N by the Alazani-Äyrichi intermontaine basin, and from the Lesser Caucasus to the S by the Kura basin. To test the hypothesis that over half of total Arabia-Eurasia convergence since...

The geological sciences are challenged to manage and interpret increasing volumes of data as observations and simulations increase in size and complexity. For example, simulations of earthquake-related processes typically generate complex, time-varying data sets in two or more dimensions. To facilitate interpretation and analysis of these data sets...

The W-NW-trending, ~1000 km long Greater Caucasus Mountains lie between the Black and Caspian Seas to the west and east, respectively, forming the northernmost edge of the Arabia-Eurasia collision zone. This belt lies nearly 550 km north of the Bitlis Suture, and is separated from the Lesser Caucasus and East Anatolian plateau to the south by the K...

Although the Altyn Tagh Fault (ATF), Xinjiang, China, is a first-order structure within the Indo-Asian collision zone, its Holocene paleoseismic and slip history remain contested. Studies of offset fluvial terraces and other landforms indicate slip rates of 9-27mm/yr over millennial timescales. However, little is known about the record of paleoeart...

The active, left-slip Altyn Tagh Fault (ATF) defines the northern boundary of the Tibetan Plateau and is among the world's longest intracontinental strike-slip faults. Despite a decade of concentrated work, the Holocene slip rate for the central ATF is still disputed, with millennial slip rates derived from faulted landforms ranging from 9 to 27 mm...

As terrestrial LiDAR scanning systems become increasingly available, strategies for executing efficient field surveys in settings without access to the power grid are increasingly needed. To evaluate scan methods and develop an off-grid power system, we used a tripod-mounted laser scanner to create high resolution (≤40 mm point spacing) topographic...

Slip rates are heavily contested for many of the first-order strike–slip faults within the Indo–Asian collision zone. Rates determined geodetically are generally lower than those reported using reconstructions of offset landforms, and it is unclear if this discrepancy reflects true secular variation in slip history, systematic errors in interpretat...

Recent and ongoing space missions are yielding new multispectral data for the surfaces of Earth and other planets at unprecedented rates and spatial resolution. With their high spatial resolution and widespread coverage, these data have opened new frontiers in observational Earth and planetary science. But they have also precipitated an acute need...

Previous studies of the active, left-slip Altyn Tagh Fault have produced two apparently contradictory Holocene slip rates for this first-order structure within the Indo-Asian collision zone. Whereas GPS and paleoseismic studies indicate a rate of ~10 mm/yr over the last 0.01 ka and 0.5 to ~3 ka, respectively, reconstructions of displaced and dated...

We present an interactive, real-time mapping system for use with digital elevation models and remotely sensed multispectral imagery that aids geoscientists in the creation and interpretation of geologic/neotectonic maps at length scales of 10 m to 1000 km. Our system provides a terrain visualization of the surface of the Earth or other terrestrial...

To advance research and improve the scientific return on data col- lection and interpretation efforts in the geosciences, we have devel- oped methods of interactive visualization, with a special focus on immersive virtual reality (VR) environments. Earth sciences em- ploy a strongly visual approach to the measurement and analysis of geologicdatadue...

Determining accurate fault slip rates at 1 ka to 1 Ma timescales requires well-constrained palinspastic reconstructions of dateable geomorphic and/or geologic markers. Although general kinematic models have been developed to simultaneously reconstruct both bedrock (e.g. bedding and fault attitudes) and neotectonic markers (e.g. strath terraces) alo...

Many studies of active, strike-slip fault systems have focused on both short-term (0-10 ka) and long-term (>5 Ma) strain, but less attention has focused on how such systems evolve at intermediate (10 ka to 1 Ma) timescales. Sophisticated models of evolving fault geometry at such intermediate timescales are particularly needed. To address this probl...

To better understand the mechanics of restraining double bends and the strike-slip faults in which they occur, we investigated the relationship between topography and bedrock structure within the Akato Tagh, the largest restraining double bend along the active, left-slip Altyn Tagh fault. The bend comprises a similar to90-km long, east-west strikin...

We investigated active deformation within the Akato Tagh restraining double bend to determine the age of the active Altyn Tagh fault relative to the Altyn Tagh system and thereby evaluate the extent to which this system evolved by net strain-hardening or softening. Active structures were mapped based on their geomorphology and disruption of Quatern...

1] The >300-km long, east striking Lapeiquan fault lies in the eastern Altyn Tagh range along the northern margin of the Tibetan Plateau and was interpreted as a north dipping thrust in early studies. However, our mapping shows that the fault is a south dipping normal fault juxtaposing Archean-Proterozoic gneisses beneath an early Paleozoic volcani...

Reconstructing deformation along the northwestern margin of the Tibetan Plateau is critical for evaluating the relative importance of microplate versus continuum models of the Indo-Asian collision. Questions regarding this margin's evolution are as follows: (1) What is the total offset along the sinistral Altyn Tagh strike-slip system? (2) How has...

The active left-slip Altyn Tagh fault defines the northern edge of the Tibetan plateau. To determine its deformation history we conducted integrated research on Cenozoic stratigraphic sections in the southern part of the Tarim Basin. Fission-track ages of detrital apatites, existing biostratigraphic data, and magnetostratigraphic analysis were used...

The Altyn Tagh fault accommodates sinistral motion between the Tibetan Plateau and the Tarim block within the India-Eurasia collision zone. We used well-preserved evidence for surface-rupturing earthquakes to reconstruct the earthquake history for the central Altyn Tagh fault. We identified three geometric fault segments bounded by left steps and a...