6 Recent studies attribute land double-frequency (DF) microseism observations to deep7 water generation. Here we show that near-coastal generation is generally the dominant 8 source region. This determination is based on observations at land and ocean seismic 9 stations, buoys, gravity wave hindcasts, and on beamforming results from continental 10 seismic arrays. Interactions between opposing o...

[1] We study the scaling relationships of source parameters and the self-similarity of earthquake spectra by analyzing a cluster of over 400 small earthquakes (ML = 0.5 to 3.4) recorded by the Anza seismic network in southern California. We compute P, S, and preevent noise spectra from each seismogram using a multitaper technique and approximate source and receiver terms by iteratively stacking...

Fractures play an important role in most carbonate and unconventional reservoirs. Precise identification of fractures and their associated properties from seismic data have significant impact on reservoir management and hydrocarbon recovery. Traditional seismic methods for fracture identification and characterization, such as shear birefringence and amplitude variations with offset and azimuth,...

Sudden drops of the beam lifetime ascribed to the capture of positively charged macroparticles (‘dust’) are observed at many high-energy electron storage rings. A trapped macroparticle has a certain thermal lifetime due to energy transfer from the beam; the interplay of different ionizing and discharging processes gives rise to an equilibrium charge. The beam lifetime is reduced by bremsstrahlu...

[1] Recent studies attribute land double-frequency (DF) microseism observations to deep water generation. Here we show that near-coastal generation is generally the dominant source region. This determination is based on observations at land and ocean seismic stations, buoys, gravity-wave hindcasts, and on beamforming results from continental seismic arrays. Interactions between opposing ocean w...

refractor ambiguities are big problem in seismic refraction method especially in seismic engineering. there can be hidden subsurface geological phenomena such as hidden faults and shear zones which are not simply predicted by the travel-time graph or some geophysical methods. head wave amplitudes are used to show the resolution of refractor ambiguities and the existence of anisotropy in complex...

Conventional crosswell surveys are expensive because a source must be placed downhole, which means that the hole must be prepped and placed off-line for a number of days. We suggest an interesting but unproven alternative: place a source on the surface, drop a simple obstruction-like device downhole that scatters tube wave arrivals from the surface source, and use the scattered tube waves energ...

We study cosmological effects of explicit Peccei-Quinn breaking on the QCD axion dark matter. find that abundance decreases or increases significantly depending initial position, even for a tiny satisfies experimental bound neutron electric dipole measurements. If first starts to oscillate around wrong vacuum and if it gets trapped there until false disappears due non-perturbative effects, its ...

Some of the most important methods for multiple suppression are based on the moveout difference between the hyperbolas corresponding to primary and multiple reflections in a CMP gather. This moveout difference is exploited by means of the Parabolic Radon Transform. In this case study I review the methodology and show the result of its application to a 2-D land seismic line are. Of particular im...