From Oligocene to Recent times a series of tectomcally controlled coastal embayments fonned on the Pacific fore-arc side of the southern Central American island-arc system. Each of these basins shows characteristic stratal geometries and facies distributIOns reflecting the complex interaction of changes of sea level. volcaniclastic input. and tectonic activity (subsidence, uplift). Sequential s...

For the past 80 years, the energy released in great strike-slip and thrust earthquakes has occurred in alternating cycles of 20 to 30 years. This pattern suggests that a global transfer mechanism from poloidal to toroidal components of tectonic plate motions is operating on time scales of several decades. The increase in seismic activity in California in recent years may be related to an accele...

Induced earthquakes currently pose a significant hazard in the central United States, but there is considerable uncertainty about the severity of their ground motions. We measure stress drops of 39 moderate-magnitude induced and tectonic earthquakes in the central United States and eastern North America. Induced earthquakes, more than half of which are shallower than 5 km, show a comparable med...

[1] Regional 2D multichannel seismic, borehole, dredge and outcrop data, together with burial models for strata in southwest Iberia, are used to investigate the tectono-stratigraphic signature of multiphased rifting on divergent margins. Our burial model reveals that Mesozoic extension occurred during three main phases, each comprising distinct subsidence pulses separated by short-lived periods...

The lithosphere, which includes the crust and the uppermost part of the mantle, is the mechanically strong outer shell of the Earth. The lithosphere is broken into a dozen or so pieces, called the tectonic plates. Constant motions between these tectonic plates cause lithospheric deformation, which leads to mountain building, earthquakes, and many other geological processes, including geohazards...

[1] A simple dynamic model based on boundary layer theory shows that dynamic topography is unlikely to vary significantly in response to short term ( 20 Myr) variations in the mean tectonic velocity. Tectonic velocities essentially mirror variations in mantle viscosity, but are not indicative of substantial modification of dynamic topography, which primarily reflects mass anomalies in the mantl...

Geologic and chronometric studies of alluvial fan sequences in south-central Australia provide insights into the roles of tectonics and climate in continental landscape evolution.The most voluminous alluvial fans in the Flinders Ranges region have developed adjacent to catchments uplifted by Plio-Quaternary reverse faults, implying that young tectonic activity has exerted a ¢rstorder control on...