نتایج جستجو برای: mantle and moho
تعداد نتایج: 16831278 فیلتر نتایج به سال:
[1] We analyze teleseismic P waves from four Mw ≥ 6.5 earthquakes recorded by a petroleum industry survey in Long Beach, California. The survey used a 2-D array with up to 5200 seismometers, 120m mean spacing, and 7 – 10 km aperture. At frequencies near 1Hz, P wave travel times and amplitudes exhibit coherent lateral variations over scales as short as ~400m, including locally delayed travel tim...
Deep long-period events (DLP events) or deep low-frequency earthquakes (deep LFEs) are deep earthquakes that radiate low-frequency seismic waves. While tectonic deep LFEs on plate boundaries are thought to be slip events, there have only been a limited number of studies on the physical mechanism of volcanic DLP events around the Moho (crust-mantle boundary) beneath volcanoes. One reasonable mec...
The Moho discontinuity plays an important role in crustal growth and evolution. In this study, we delineate the geometry southern California by jointly using local Moho-reflected waves PmP teleseismic Moho-converted Ps. To well constrain geometry, have developed a two-stage process to pick created reliable travel time data set with total of 10,192 picks. We also extracted 38,648 high-quality P-...
[1] Uppermost mantle seismic structure below the Southern Alps in South Island, New Zealand, is investigated by teleseismic P wave travel time residual inversion. The three-dimensional tomographic images show a near-vertical, high-velocity (2–4%) structure in the uppermost mantle that directly underlies thickened crust along the NNESSW axis of the Southern Alps. The center of the high-velocity ...
The application of the pre-stack depth migration (PSDM) method using deep seismic reflection data is still a challenge. In this paper, dataset collected from Bohai Bay Basin used to test applicability method. After improving signal-to-noise ratio prestack gathers and building an accurate velocity model capturing lateral vertical variations, high-quality profile obtained. This shows detailed cru...
[1] Broadband data from the Meso-America Subduction Experiment (MASE) line in central Mexico were used to image the subducted Cocos plate and the overriding continental lithosphere beneath central Mexico using a generalized radon transform based migration. Our images provide insight into the process of subducting relatively young oceanic lithosphere and its complex geometry beneath continental ...
P waves from regional-distance earthquakes are complex and reverberatory, as would be expected from a combination of head waves, post-critical crustal reflections and shallow-incident P waves from the upper mantle. Although designed for steeply-incident teleseismic P waves, receiver functions (RFs) can also retrieve information about crustal structure from regional P. Using a new computation me...
The Makran Subduction Zone is the primary seismic/tsunami hazard of northwestern Indian Ocean, but little known its on-shore seismic structure. We derived a shear wave velocity model extending to 100 km depth beneath ∼400 km-long profile oriented parallel convergence vector Arabian Sea Plate. Receiver function/surface analysis shows that average structure in coastal region comprises ∼22–28 km-t...
Abstract The Taiwan orogenic belt is formed by the strong convergence between Philippine Sea Plate and Eurasian Plate. detailed mountain building process still under debated largely due to poor constraint of deep crustal structures, particularly geometry at Moho-depth. Here Moho-refracted P waves are identified from seismic data recorded a dense array (Formosa Array) in northern Taiwan. Althoug...
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