Mapping a part of Neuquen Basin in Argentina by global-phase H/V spectral ratio

We investigated the applicability of global phases (epicentral distances of ? 120° and ? 150°) for the H/V spectral ratio to identify the fundamental resonance frequency. We applied the method to delineate a part of Neuquén basin in Argentina without the need for active seismic sources. We obtained fairly identifiable fundamental resonance...

Quality-factor and reflection-coefficient estimation using reflected surface waves

We propose a method for estimating the reflection coefficient of a subvertical boundary and the the quality factor of the medium between a receiver and the subvertical boundary. The method uses surface waves from transient deterministic sources and is inspired by the occurrence of non-physical arrivals in seismic-interferometry results due to...

Global-phase H/V spectral ratio for delineating the basin in the Malargüe Region, Argentina

Structural estimation of unconsolidated sediments and basins is of fundamental importance for resources exploration, geohazard assessments, and other geophysical aspects. The estimation contributes not only to the understanding of the tectonic settings, but also to the choice of parameters for possible further seismic processing, for example,...

Shear wave seismic interferometry for lithospheric imaging: Application to southern Mexico

Seismic interferometry allows for the creation of new seismic traces by cross correlating existing ones. With sufficient sampling of remote-source positions, it is possible to create a virtual source record by transforming a receiver location into a virtual source. The imaging technique developed here directly retrieves reflectivity information...

Monitoring changes in velocity and Q using non-physical arrivals in seismic interferometry

Application of seismic interferometry to records from receivers at the Earth’s surface from sources in wells retrieves the reflection response measured at the receivers as if from virtual sources located also at the surface. When the wavefields experience intrinsic losses during propagation, non-physical arrivals (ghosts) would appear in the...

Seismic interferometry by midpoint integration

With seismic interferometry reflections can be retrieved between station positions. In the classical form, the reflections are retrieved by an integration over sources. For a specific dataset, however, the actual source distribution might not be sufficient to approximate the source integral. Yet, there might be a dense distribution of receivers...

A modified delay-time method for statics estimation with the virtual refraction

Topography and near-surface heterogeneities lead to traveltime perturbations in surface land-seismic experiments. Usually, these perturbations are estimated and removed prior to further processing of the data. A common technique to estimate these perturbations is the delay-time method. We have developed the “modified delay-time method,” wherein...

Body-wave seismic interferometry applied to earthquake- and storm-induced wavefield

Seismology is the study of the vibration of the Earth. Seismologists pay much attention to the main source of Earth vibration: earthquakes. But also other seismic sources, like mining blasts, ocean storms and windmills, are studied. All these sources induce seismic waves, which can eventually be recorded as ground vibrations. These seismic...

Global-phase seismic interferometry unveils P-wave reflectivity below the Himalayas and Tibet

A number of seismic methods exist to image the lithosphere below a collection of receivers, using distant earthquakes. In the current practice, especially mode-conversions in teleseismic phases are utilized. We present a new method that takes advantage of the availability of global phases. This method is called global-phase seismic...

Scanning for velocity anomalies in the crust and mantle with diffractions from the core-mantle boundary

A novel method, based on differential arrival times of diffractions from the core-mantle boundary, swiftly scans for seismic velocity anomalies in the crust and mantle below an array of seismometers. The method is applied to data from the USArray and the large-scale structural features in the western United States are resolved. High lateral...