Different forms of fluctuations of the terrestrial gravity field are observed by gravity experiments. For example, atmospheric pressure fluctuations generate a gravity-noise foreground in measurements with super-conducting gravimeters. Gravity changes caused by high-magnitude earthquakes have been detected with the satellite gravity experiment GRACE, and we expect high-frequency terrestrial gra...

This paper proposes using microphone recordings of air waves, recorded close to a geophone, to suppress air-wave noise on the geophone. The types of air-wave noise on the geophone may include air-coupled ground roll, air blast, ground-coupled air blast, and wind noise. Microphone recordings of air waves are related to ground measurements and geophone disturbances. We can thus attempt to use the...

Many of the geophysical data analysis problems, such as signal-noise separation and data regularization, are conveniently formulated in a transform domain, where the signal appears sparse. Classic transforms such as the Fourier transform or the digital wavelet transform, fail occasionally in processing complex seismic wavefields, because of the nonstationarity of seismic data in both time and s...

seismic coherency is a measure of lateral changes in acoustic impedance that are caused by variations in structure, stratigraphy, lithology, porosity, and fluid content. seismic coherency is a geometrical attribute that establishes temporal and lateral relationships with other attributes. seismic coherency can be defined by coherency attributes. when coherency attributes are applied to seismic ...

Seismic and acoustic noise from moving tracked vehicles was used to determine the seismic to acoustic signal coupling ratio (SAR) in the ground. The seismic signal received on a geophone contains some energy that has propagated as seismic waves and some energy that couples from acoustic waves to seismic waves in the vicinity of the geophone. We use the frequency domain coherence between the mic...

In this study, we cross-correlate waveforms of ambient seismic noise between 6 and 100 sec to study the origin of ambient seismic noise. We use one year of data recorded at numerical stations located in Europe, North America, and southern Africa. We measure the signal-to-noise ratios (SNR) of Rayleigh waves for positive and negative correlation time lags at periods of 8, 14, 25 and 50 sec to de...

Article history: Imaging using information Received 15 April 2008 Received in revised form 16 November 2008 Accepted 18 November 2008 Available online 28 November 2008

We present a preliminary study of the dependence of the fractal features of the soil motion due to seismic noise on the near-surface geology in the frequency range from 1 Hz to ∼ 40 Hz. In detail, we have investigated the 3-d average squared soil displacement 〈r〉 and the distribution function of the displacement fluctuations in different geological sites. The anomalous scaling of the average sq...

Missing trace reconstruction is a challenge in seismic processing due to incomplete and irregular acquisition. Noise is a concern, due to the many sources of noise that occur during seismic acquisition. Most of the recent research on denoising and interpolation focuses on transform domain approaches using L1 norm minimization. A specific kind of constraint, called the synthesis approach, is wid...

In interferometric gravitational wave detectors such as LIGO, the mirrors are suspended on fine wires. In designs for advanced detectors, the pendulums where the mirrors hang have multiple stages with both horizontal and vertical soft spring constants. The pendulum frequencies (around or below 1 Hz) are much lower than the frequency with optimal sensitivity for gravitational waves (around 100 H...