Samples of fault gouge from the San Andreas Fault drill hole (SAFOD), a shale from the North Sea sedimentary basin and schists from metamorphic rocks in the Alps have been analyzed with high energy synchrotron X-rays to determine preferred orientation of mica and clay minerals. The method relies on obtaining 2D diffraction images which are then processed with the crystallographic Rietveld metho...

[1] To understand the role of hydrated clay minerals in active fault systems, a humidity chamber connected to an X-ray diffractometer was used to determine the adsorption of water onto and/or into the crystal structure of smectite. This new type of analysis was carried out under specific temperature and humidity conditions, using powdered clay size fractions (< 2 mm) of rock samples from the Sa...

The Boumerdes-Algiers earthquake of magnitude Mw:6.8 is the second major event which seriously affected Algeria in the last twenty years. This seismic event, located 7 km north of the village of Zemmouri (50 Km east of Algiers) happened in a region characterized previously by a low to moderate seismic activity. With a depth of 10 km, the earthquake killed 2300 persons and caused huge damage in ...

[1] NEAR Shoemaker images reveal widespread occurrence of tectonic landforms on asteroid 433 Eros. Hinks Dorsum is a ridge that extends for about 18 km around the asteroid and strongly resembles thrust fault structures on the terrestrial planets. Tectonic landforms can provide information on the mechanical properties of asteroids, a subject of much controversy. Modeling constrained by topograph...

[1] Low-velocity fault zones (LVFZs) are found in most mature faults. They are usually 100–400 m wide and have 20%–60% wave velocity reductions relative to the country rock. To study the effect of LVFZs on earthquake rupture and the radiated wavefield, we conducted two-dimensional (2-D) simulations of dynamic rupture on faults that bisect a LVFZ, considering a range of velocity reductions and w...

Numerical models based on linear elasticity theory predict asymmetric slip distribution with a steep slip gradient near the line of intersection of intersecting normal faults. They also predict a discrepancy between the direction of slip on the fault plane and the direction of resolved shear stress. Both variations in slip magnitude and direction are due to mechanical interaction between the fa...