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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:07 |
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Conference: Bucharest University Faculty of Physics 2016 Meeting
Section: Atmosphere and Earth Science; Environment Protection
Title:
Improve earthquakes location using a multi-scale frequency-selective analysis - a case study
Authors:
Dragos TATARU, Natalia POIATA, Bogdan GRECU, Mihaela POPA, Mircea RADULIAN
Affiliation:
National Institute for Earth Physics, Magurele, Romania
E-mail
dragos@infp.ro
Keywords:
earthquake, anthropic and natural seismicity, detection, tremors
Abstract:
Seismology is currently in the stage of transformative progress based upon a simultaneous surge in instrumentations, software and hardware. Modern seismic networks can be regarded as arrays, or antennas, of increasing density and spatial coverage, recording high-quality, time-continuous signals, making it possible to explore time and frequency scales at which seismic sources were essentially unknown. At the same time, dense seismic networks generate increasing volumes of data, which represent a challenge for the current “classical” source detection and extraction methodologies.The most common scheme for automatic detection and location of earthquakes is based on a three-step procedure consisting of phase picking, association and source location through travel time inversion.The main drawback of such approaches is that the phase picking is often done on individual seismograms, making no use of information about the coherency between the stations. This can lead to missed detection and reduces location resolution, in the case of complex seismic sequences with multiple (overlapping) events such as seismic swarms, or foreshock and aftershock activity. To overcome these shortcoming, a significant effort has been recently applied to develop efficient automatic detection and location methods converting time-continuous seismic signals recorded at different stations into time series of 3D coherent spatial images, through reverse propagation, delay-and-sum or migration techniques [1]. Such method for detection and location of seismic sources based on multi-scale frequency-selective analysis of continuous full waveform recordings was applied on a subset of seismic data recorded during the 2013 Galati earthquake swarm episode[2] demonstrate that fully automatic schemes based on advanced signal-processing and array detection and location techniques can provide a more revealing picture of the space-time distribution of the seismic energy release process.
References:
1.Poiata, N., Satriano C.,Bernard P.,Vilotte J.P.,Obara K., Multi-band array detection and location of seismic sources recorded by dense seismic networks, Geophys. J. Int., doi:10.111/j.1365-246X.2012.05602.x., 2004
2.Popa, M., et al. "The 2013 Earthquake Swarm in the Galati Area: First Results for a Seismotectonic Interpretation." The 1940 Vrancea Earthquake. Issues, Insights and Lessons Learnt. Springer International Publishing, pp 253-265, 2015.
Acknowledgement:
This work was done in the framework of project PN 16 35 03 02 /2016 supported by the Romanian Ministry of Education and Scientific Research.
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