Charles Cashman Trexler

• PhD
• Fellow at United States Geological Survey

Seismic sources and their associated hazards within the Sacramento-San Joaquin Delta region of north-central California are relatively poorly characterized as compared to other, more heavily studied regions of northern California, such as the San Francisco Bay Area. Here we present a synthesis of subsurface, bedrock geology, and geodetic datasets f...

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...

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 ~...

The Great Valley fault system defines the tectonic boundary between the Coast Ranges and the Central Valley in California, is active throughout the Quaternary, and has been the source of several significant (M > 6) historic earthquakes, including the 1983 M 6.5 Coalinga earthquake and the 1892 Vacaville–Winters earthquake sequence. However, the loc...

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 detailed features of an earthquake surface rupture may decay quickly in the landscape due to erosion or repair, such that primary displacements are seldom available for repeated study within the weeks following an earthquake. Here we describe a rapidly deployable field workflow using structure-from-motion (SfM) photogrammetry to produce three-d...

Key Points The Greater Caucasus Basin encompassed a broader region than envisioned by Vincent et al., who disregard Cenozoic shortening Terminal basin closure occurred when the Greater and Lesser Caucasus collided Data cited by Vincent et al. document the onset of basin closure by 35 Ma, but do not indicate terminal basin closure at this time

The Caucasus defines the northern margin of the Arabia-Eurasia collision zone between the Black and Caspian Seas, within the Alpine Himalayan collision. Most orogen perpendicular convergence within this sector of the Arabia-Eurasia collision is absorbed within the Greater Caucasus, as indicated by seismicity, GPS velocity gradients and Neotectonic...

Comparison of plate convergence with the timing and magnitude of upper-crustal shortening in collisional orogens indicates both shortening deficits (200-1700 km) and significant (10-40%) plate deceleration during collision, the cause(s) for which remain debated. The Greater Caucasus Mountains, which result from post-collisional Cenozoic closure of...

Online Material: Color versions of Figures 1–4; Google Earth file with imbedded field photos. Surface‐rupture observations constrain the orientation, length, and direction of fault slip and are especially useful in the information‐limited immediate aftermath of a large earthquake. The extent of surface rupture and preliminary slip observations are...

The Greater Caucasus Mountains contain the highest peaks in Europe and define, for over 850 km along strike, the leading edge of the second-largest active collisional orogen on Earth. However, the mechanisms by which this range is being constructed remain disputed. Using a new database of earthquake records from local networks in Georgia, Russia, a...