Lizurek, Grzegorz and Marmureanu, A. and Wiszniowski, Jan (2017) Fast Moment Magnitude Determination from P-wave Trains for Bucharest Rapid Early Warning System (BREWS). Pure and Applied Geophysics, 174 (3). pp. 1489-1502. DOI: https://doi.org/10.1007/s00024-017-1480-7
Full text not available from this repository.Abstract
Bucharest, with a population of approximately 2 million people, has suffered damage from earthquakes in the Vrancea seismic zone, which is located about 170 km from Bucharest, at a depth of 80–200 km. Consequently, an earthquake early warning system (Bucharest Rapid earthquake Early Warning System or BREWS) was constructed to provide some warning about impending shaking from large earthquakes in the Vrancea zone. In order to provide quick estimates of magnitude, seismic moment was first determined from P-waves and then a moment magnitude was determined from the moment. However, this magnitude may not be consistent with previous estimates of magnitude from the Romanian Seismic Network. This paper introduces the algorithm using P-wave spectral levels and compares them with catalog estimates. The testing procedure used waveforms from about 90 events with catalog magnitudes from 3.5 to 5.4. Corrections to the P-wave determined magnitudes according to dominant intermediate depth events mechanism were tested for November 22, 2014, M5.6 and October 17, M6 events. The corrections worked well, but unveiled overestimation of the average magnitude result of about 0.2 magnitude unit in the case of shallow depth event (H\60 km). The P-wave spectral approach allows for the relatively fast estimates of magnitude for use in BREWS. The average correction taking into account the most common focal mechanism for radiation pattern coefficient may lead to overestimation of the magnitude for shallow events of about 0.2 magnitude unit. However, in case of events of intermediate depth of M6 the resulting Mw is underestimated at about 0.1–0.2. We conclude that our P-wave spectral approach is sufficiently robust for the needs of BREWS for both shallow and intermediate depth events.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Earthquake early warning system, spectral parameters,magnitude, Vrancea |
| Subjects: | Methodology > Method and procesing > Source parameter estimation Methodology > Method and procesing > Collective properties of seismicity |
| Project: | IS-EPOS project |