Source scaling properties are studied for the intermediate-depth seismic nest in the Vrancea region, Romania, which has been the source of many destructive earthquakes. We investigate spectral and time-domain scaling properties using wide-band digital records from 16 earth- quakes (3.7 ≤ MW ≤ 7.4). All processing variants (P or S waves, spectral or time domain, etc.) produceconsistentresults.Theobservedcorner-frequencyversusMW trendgenerallyfollows the constant-stress-drop model, with typical stress-drop values of 1–10 MPa. This kind of scaling, seen over the entire magnitude range analysed, is similar to that observed for shallow events. However, this trend seems to be violated for the largest earthquakes (MW > 6.5). They show a clear tendency for higher static stress drops than shallow events, and for magnitudes above 7, average stress drops exceeding 10 MPa may be expected. These results are of partic- ular significance for seismic hazard studies, and specifically for the estimation of future strong motions.

Source scaling of intermediate-depth Vrancea earthquakes.

PANZA, GIULIANO
2002-01-01

Abstract

Source scaling properties are studied for the intermediate-depth seismic nest in the Vrancea region, Romania, which has been the source of many destructive earthquakes. We investigate spectral and time-domain scaling properties using wide-band digital records from 16 earth- quakes (3.7 ≤ MW ≤ 7.4). All processing variants (P or S waves, spectral or time domain, etc.) produceconsistentresults.Theobservedcorner-frequencyversusMW trendgenerallyfollows the constant-stress-drop model, with typical stress-drop values of 1–10 MPa. This kind of scaling, seen over the entire magnitude range analysed, is similar to that observed for shallow events. However, this trend seems to be violated for the largest earthquakes (MW > 6.5). They show a clear tendency for higher static stress drops than shallow events, and for magnitudes above 7, average stress drops exceeding 10 MPa may be expected. These results are of partic- ular significance for seismic hazard studies, and specifically for the estimation of future strong motions.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/1698614
 Avviso

Registrazione in corso di verifica.
La registrazione di questo prodotto non è ancora stata validata in ArTS.

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact