Vibroseis is a method that imparts coded seismic energy into the ground. The energy is recorded with geophones and then processed using the known (coded) input signal. The resulting time-domain representation of vibroseis data is an impulsive wavetrain with wavelet properties consistent with the coded input signal convolved with the earth’s reflectivity series. Historically vibratory seismic su...

There are numerous methods for interpolating uniformly sampled, aliased seismic data, but few can handle the combination of nonuniform sampling and aliasing. We combine the principles of Fourier reconstruction of nonaliased, nonuniformly sampled data with the ideas of frequency-wavenumber f-k interpolation of aliased, uniformly sampled data in a new two-step algorithm. In the first step, we est...

Common-midpoint (CMP) stacking technique plays an important role in enhancing the signal-to-noise ratio (SNR) in seismic data processing and imaging. Weighted stacking is often used to improve the performance of conventional equalweight stacking in further attenuating random noise and handling the amplitude variations in real seismic data. In this study, we propose to use a hybrid framework of ...

Correlation of the coda of large earthquakes can be used to retrieve body waves at teleseismic distances. This retrieval depends on waves propagating with equal energy in all directions (equipartitioning). We carry out a beamforming analysis of body waves at periods of 10 and 40 s recorded at USArray and show that the late coda, up to 10 h after the Okhotsk earthquake, is dominated by waves pro...

A comparative analysis was performed on datasets from two Global Seismographic Network (GSN) stations near the South Pole, Antarctica. The results of this analysis are provided and show that there is significant reduction of the background seismic noise generated by the activities at the Amundsen-Scott South Pole Station as a function of distance and depth. Data gathered from site selection wor...

nonlinear static procedure (nsp) is a common technique to predict seismic demands on various building structures by subjecting a monotonically increasing horizontal loading (pushover) to the structure. therefore, the pushover analysis is an important part of each nsp. accordingly, the current paper aims at investigating the efficiencyof various algorithms of lateral load patterns applied to the...

Continuous seismic records near river channels can be used to quantify the energy induced by river sediment transport. During the 2011 typhoon season, we deployed a seismic array along the Chishan River in the mountain area of southern Taiwan, where there is strong variability in water discharge and high sedimentation rates. We observe hysteresis in the high-frequency (5-15 Hz) seismic noise le...

This paper discusses the processes and mechanical factors that define the seismogenic zone and the updip transition from seismic to aseismic faulting. We review friction laws for granular and clay-rich fault zones and discuss them in the context of the mechanics of stick-slip and the requirements for instability. Seismogenic faulting is driven by the unstable release of stored elastic energy, a...

On 23 June 2014, the largest intermediate depth earthquake (Mw 7.9) of the last 100 years ruptured within the subducting Pacific plate about 100 km below the Rat Islands archipelago of the Western Aleutian Islands, Alaska. The unusual faulting orientation, strike = 206°, dip = 24°, and rake = 14°, is possibly related to curvature of the underthrust slab and high obliquity of the relative plate ...

Aims. We suggest an explanation for the high-frequency power excess surrounding active regions known as seismic halos. Methods. We use numerical simulations of magneto-acoustic wave propagation in magnetostatic sunspot model. Results. We propose that seismic halos can be caused by the additional energy injected by high-frequency fast mode waves refracted in the higher atmosphere due to the rapi...