000006614 001__ 6614
000006614 005__ 20240122155212.0
000006614 037__ $$aCTALK-2024-0013
000006614 100__ $$aVanneste, Kris
000006614 245__ $$aMagnitude reassessment for digital records of the Belgian seismic network since 1985
000006614 260__ $$c2023
000006614 269__ $$c2023-07-17
000006614 520__ $$aIn the frame of the BELSHAKE project, we collected all digital records by the Belgian seismic network of earthquakes with ML>2 in a dedicated waveform archive and the associated metadata in a database. We visually inspected all waveforms, calculated missing P- and S- arrival times from the Belgian velocity model, and defined noise, P-, S- and coda-windows. We also developed the tools to recompute local magnitudes and to compute new moment magnitudes. One of the main problems we encountered was missing instrument response information for older records. We tried to reconstruct this information based on information in our station database and/or the original data headers. Analysis of station ML residuals and PSDs of the noise window allowed to select the correct response or to identify unreliable cases. The definition of the Belgian ML scale is based on the Lg wave on the vertical component high-pass filtered at 1 Hz. It has been applied systematically since 1985, but unfortunately not all amplitude measurements are preserved in the database. Furthermore, the scale has not been calibrated for distances < 10 km and does not take into account hypocentral depth. These issues are problematic to determine ML of recent shallow geothermally induced seismicity. We will use our dataset to derive a better formulation of the Belgian ML scale. We also compute MW based on spectral fitting of P- and S-waves with the well-known sourcespec package. This will eliminate the need for empirical magnitude scale conversions to compute magnitude-frequency relations for seismic hazard assessment.
000006614 536__ $$aBRAIN_BELSHAKE/$$cBRAIN_BELSHAKE/$$fBRAIN_BELSHAKE
000006614 594__ $$aNO
000006614 700__ $$aOnvani, Mahsa
000006614 700__ $$aCamelbeeck, Thierry
000006614 700__ $$aLecocq, Thomas
000006614 700__ $$aRapagnani, Giovanni
000006614 773__ $$tIUGG 28th General Assembly, Berlin (Germany)
000006614 8560_ $$fkris.vanneste@ksb-orb.be
000006614 906__ $$aContributed
000006614 980__ $$aCTALKCONT