Journal ArticleDOI
Automatic phase pickers: Their present use and future prospects
TLDR
Automatic phase-picking algorithms are designed to detect a seismic signal on a single trace and to time the arrival of the signal precisely as mentioned in this paper, but they are inherently less sensitive than one designed only to detect the presence of a signal, but still can approach the performance of a skilled analyst.Abstract:
Automatic phase-picking algorithms are designed to detect a seismic signal on a single trace and to time the arrival of the signal precisely. Because of the requirement for precise timing, a phase-picking algorithm is inherently less sensitive than one designed only to detect the presence of a signal, but still can approach the performance of a skilled analyst. A typical algorithm filters the input data and then generates a function characterizing the seismic time series. This function may be as simple as the absolute value of the series, or it may be quite complex. Event detection is accomplished by comparing the function or its short-term average (STA ) with a threshold value (THR), which is commonly some multiple of a long-term average (LTA) of a characteristic function. If the STA exceeds THR, a trigger is declared. If the event passes simple criteria, it is reported. Sensitivity, expected timing error, false-trigger rate, and false-report rate are interrelated measures of performance controlled by choice of the characteristic function and several operating parameters. At present, computational power limits most systems to one-pass, time-domain algorithms. Rapidly advancing semi-conductor technology, however, will make possible much more powerful multi-pass approaches incorporating frequency-domain detection and pseudo-offline timing.read more
Citations
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Journal ArticleDOI
Initial reference models in local earthquake tomography
TL;DR: In this article, the same inversion formalism was used to determine hypocenters and one-dimensional (1-D) velocity model parameters, including station corrections, as the first step in the 3D modeling process.
Journal ArticleDOI
Convolutional neural network for earthquake detection and location
TL;DR: ConvNetQuake as discussed by the authors is a scalable convolutional neural network for earthquake detection and location from a single waveform, which was applied to study the induced seismicity in Oklahoma, USA.
Journal ArticleDOI
A comparison of select trigger algorithms for automated global seismic phase and event detection
Mitchell M. Withers,Richard C. Aster,Christopher John Young,J.I. Beiriger,Mark Harris,S.G. Moore,Julian Trujillo +6 more
TL;DR: While no algorithm was clearly optimal under all source, receiver, path, and noise conditions tested, an STA/LTA algorithm incorporating adaptive window lengths controlled by nonstationary seismogram spectral characteristics was found to provide an output that best met the requirements of a global correlated event-detection and location system.
Journal ArticleDOI
Geotomography with local earthquake data
TL;DR: In this article, the Aki-Christoffersson-Husebye method (ACH) is used for the inversion of large matrices, a task that is often performed by approximative solutions when the matrices become too big, considering the coupled inverse problem.
Journal ArticleDOI
An automatic phase picker for local and teleseismic events
Manfred Baer,Urs Kradolfer +1 more
TL;DR: In this article, an automatic detection algorithm has been developed which is capable of time P -phase arrivals of both local and teleseismic earthquakes, but rejects noise bursts and transient events.
References
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Journal ArticleDOI
Automatic earthquake recognition and timing from single traces
TL;DR: In this article, a computer program was developed for the automatic detection and timing of earthquakes on a single seismic trace, which operates on line and is sufficiently simple that it is expected to work in inexpensive low-power microprocessors in field applications.
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ASP: an automated seismic processor for microearthquake networks
TL;DR: ASP as discussed by the authors is a low-power, in-field automated Seismic Processor of microearthquake network data has been designed, fabricated, and deployed for initial operation in four different field areas to monitor seismicity associated with two geothermal areas (The Geysers, California, and Cerro Prieto, Mexico), a nuclear explosion with its related collapse and aftershock sequence, and late (>1 year) activity in a major aftershock series (Livermore, California).
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Real-time detection and location of local seismic events in central California
TL;DR: A computer-based system dedicated full time to automatic detection and location of local seismic events in central California has been developed as discussed by the authors, which monitors 108 short-period vertical-component stations from the U.S. Geological Survey central California and Oroville seismic networks.
Journal ArticleDOI
An automatic seismic signal detection algorithm based on the Walsh transform
Tom Goforth,Eugene Herrin +1 more
TL;DR: An automatic seismic signal detection algorithm based on the Walsh transform has been developed for short-period data sampled at 20 samples/sec and tests indicate that the algorithm has a detection capability comparable to a human analyst.