Discussion S waves are seismic body waves meaning they travel through the Earth’s interior. Their velocity is slower than that of P waves, and they are normally the second major phase to be observed on a seismogram, and are therefore also referred to as secondary waves. In the Earth’s crust, S wave velocities are typically 3–4 km/s. S waves are usually larger in amplitude than P waves and may c...

Recently, a metastable thermal-chemical convection model was proposed to explain the African Superplume. Its bulk tabular shape remains relatively stable while its interior undergoes significant stirring with low-velocity conduits along its edges and down-welling near the middle. Here, we perform a mapping of chemistry and temperature into P and S velocity variations and replace a seismically d...

The detector algorithms in use at date rely on negative decision logic: based on a model of the ambient noise process they detect all deviations, but many of them are false alarms. The principal alternative to this approach is pattern recognition, which tests on positive correlation with some known signal patterns. The Sonogram-detector realizes this scheme for single seismogram traces. Sonogra...

In the present paper, we propose a software package developed by the authors and based on the continuous wavelet transform that allows to perform the direct and inverse continuous wavelet transform, 2C and 3C polarization analysis and filtering, modeling the dispersed and attenuated wave propagation in the timefrequency domain and optimization in signal and wavelet domains with the aim to extra...

When an earthquake occurs, seismologists want to use recorded seismograms to infer its location, magnitude and source-focal mechanism as quickly as possible. If such information could be determined immediately, timely evacuations and emergency actions could be undertaken to mitigate earthquake damage. Current advanced methods can report the initial location and magnitude of an earthquake within...

It is widely acknowledged that an important aspect in Earth Science research is the ability to visualize huge amounts of data resulting from numerical simulations or data acquisition. Whether the data is a simple two-dimensional plot or a three-dimensional multivariate grid, the ability to visualize the data is imperative for researchers to properly demonstrate results. This poster will examine...

In this paper the methods for representation theorem coupling of finite-element or finite difference calculations and propagator matrix method calculations (Harkrider) are developed. The validity and accuracy of the resulting hybrid method are demonstrated. The resulting hybrid technique can be used to study the propagation of any phase that can be represented in terms of an SH mode sum seismog...

We demonstrate a rupture front focusing phenomenon at the initial stage of earthquake, which causes high slip rate pulses and therefore generates high frequency seismic waves. In this computation, we assume a pre-slip region, where stress has already lowered quasi-statically to the dynamic friction level. And due to the pre-slip, we suppose a stress concentration at the edge of pre-slip area. T...