Seismic reflection and refraction images illuminate the San Andreas Fault to a depth of 1 kilometer. The prestack depth-migrated reflection image contains near-vertical reflections aligned with the active fault trace. The fault is vertical in the upper 0.5 kilometer, then dips about 70 degrees to the southwest to at least 1 kilometer subsurface. This dip reconciles the difference between the co...

We collected continuous seismic data recorded between 2007 and 2010 by 208 broadband stations from the Chinese Provincial Digital Seismic Networks, A Seismic Collaborative Experiment of Northern Tibet, and the Northeastern Tibet Seismic experiment. Cross correlations of vertical component records are computed to extract the Rayleigh wave empirical Green’s functions. Group and phase velocities a...

Ground motions recorded within sedimentary basins are variable over short distances. One important cause of the variability is that local soil properties are variable at all scales. Regional hazard maps developed for predicting site effects are generally derived from maps of surficial geology; however, recent studies have shown that mapped geologic units do not correlate well with the average s...

This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the [1] Interpretations of dynamic processes and the thermal and chemical structure of the Earth depend on the accuracy of Earth models. With the growing number of velocity ...

[1] High-pressure assemblages of subducted oceanic crust are denser than the normal upper mantle but less dense than the uppermost lower mantle. Thus subducted oceanic crust may accumulate at the base of the upper mantle. Direct observational evidence for this hypothesis, however, remains elusive. We present an analysis of a negativepolarity shear wave converted from compressional wave at a sei...

this paper is devoted to compiling a site geology map for town of amiriyeh, from seismic macro-zonation point of view using geophysical methods of shallow seismic, down-hole seismic and resistivity surveys. in this map site geology has been classified based on shear wave velocity, according to the criteria for site geology classification offered in the iranian code of practice for seismic resis...

We determine the three-dimensional shear wave velocity structure of the crust and upper mantle in China using Green’’s functions obtained from seismic ambient noise cross-correlation. The data we use are from the China National Seismic Network, global and regional networks and PASSCAL stations in the region. We first acquire cross-correlation seismograms between all possible station pairs. We t...

iran is located between two lithospheric plates (euroasia, arabian) and these two plates converge toward each other with a velocity of 25 mm/yr rate. shortening that produced from this convergence with makran subductin shows faulting and folding in zagros orogenic belt, alborz and kopedagh in north and sliding in sum strike slip faults with north-south trend in central iran. the nw-se trending ...

tehran, iran’s capital with a population of more than 10 million is located in the southern foothills of the alborz collision zone. the alborz mountain belt of northern iran results from the collision of a piece of the gondwana with eurasia in the late triassic (sengor et al., 1988). the alborz active mountain range which consists of several sedimentary and volcanic layers, with east-west trend...

We constrain SH and P wave velocity structures in the upper mantle beneath southern Africa, using triplicated phases recorded in the epicentral distance range of 11°–28° for one shallow event. We then explore thermal and compositional models appropriate for explaining the inferred seismic structures in the region. Both SH and P wave data suggest presence of a low velocity zone with velocity red...