In this paper we approach the problem of recovering the earth’s impulse response and the seismic wavelets used to probe the earth by the use of techniques inspired in blind equalization methods developed for digital communication systems. We present a recently proposed class of algorithms to recover, by seismogram observation only, both amplitude and phase of the seismic wavelets and the earth’...

CWI's research has a theme-oriented structure and is grouped into four clusters. Listed below are the names of the clusters and in parentheses their acronyms. 1. INTRODUCTION A feature of a seismic earthquake signal is that it is built up by several different seismic waves, characterizing the type of signal. In this paper we are only interested in two of these waves, namely the primary wave (P-...

[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...

Long-period surface waves recorded on the north-south Pasadena strainmeter are used to determine the seismic moments and fault parameters of the 19 May 1940 Imperial Valley, California, the 16 December 1954 Dixie Valley and Fairview Peak, Nevada, and the 18 August 1959 Hebgen Lake, Montana, earthquakes. Synthetic strain seismograms are matched with the observed strainmeter seismograms. Source p...

Recordings of the Earth's surface oscillation as a function of time (seismograms) can be sonified by compressing time so that most of the signal's frequency spectrum falls in the audible range. The patternrecognition capabilities of the human auditory system can then be applied to the auditory analysis of seismic data. In this experiment, we sonify a set of seismograms associated with a magnitu...

Marc Schoenauer1, Andreas Ehinger2 and Bertrand Braunschweig3 (1) : CMAP, CNRS-URA 756, Ecole Polytechnique, Palaiseau, France (2) : Geophysics and Instrumentation, IFP, Pau, France (3) : Computer Science and Applied Mathematics, IFP, Rueil-Malmaison, France E-mails : [email protected], fandreas.ehinger,[email protected] Abstract Many problems to be solved in geophysi...

[1] We present DR2012, a global SV-wave tomographic model of the upper mantle. We use an extension of the automated waveform inversion approach of Debayle (1999) which improves our mapping of the transition zone with extraction of fundamental and higher-mode information. The new approach is fully automated and has been successfully used to match approximately 375,000 Rayleigh waveforms. For eac...

In this paper, the behavior of the pseudopolynomial numerical hull of a square complex matrix with respect to structured perturbations and its radius is investigated.

Non-stationary signals are often analyzed using raw waveform data or spectrograms of those data; however, the possibility alternative time–frequency representations being more informative than original is yet to be investigated. This paper tested whether could for machine learning classification seismological data. The mentioned hypothesis was evaluated by training three well-established convol...

[1] We investigated deep slip rates along the Longmen Shan fault zone where the devastating 2008 M7.9 Wenchuan earthquake occurred using repeating earthquake data recorded by two digital seismic networks near the fault. Using cross‐correlation analysis of waveform data, we identified a total of 231 doublets and 224 multiplets that have highly similar waveforms. Most of these sequences are aperi...