Some temporary seismic stations were installed in Cilento from February to October 2014 for a monitoring of the local seismicity in the area of Roccadaspide and surrounding villages, where two earthquakes of magnitude Mw=3.6 and Mw=3.7 occurred on January 22, 2014. Following the warnings of rumbles and tremors from people living in the area, reported also by local press and television, a field survey was realized and the seismic monitoring begun. Acquired data showed a sequence of microearthquakes likely triggered by the two events occurred on January 22. We identified more than 750 very small earthquakes (M<2), of which more than 60 have been located. The 95% of the sources is located in an area of about 10 km2 with depth lower than 3 km. For about 15 earthquakes recorded by at least 5 stations we were able to compute also the focal mechanism. Results of our analysis suggest a predominant distensive dynamics in the epicentral area, although the full picture is rather complex, with significantly different mechanisms for sources very near to each other.
Alcune stazioni sismiche temporanee sono state installate nel Cilento da febbraio a ottobre 2014 per monitorare la sismicità locale nella zona di Roccadaspide e Comuni limitrofi, dove due terremoti di magnitudo Mw=3.6 e Mw=3.7 sono avvenuti il 22 gennaio 2014. In seguito alle segnalazioni di boati e tremori riportate da cittadini che abitano nella zona, diffuse anche attraverso gli organi di stampa e le televisioni locali, è stato effettuato un sopralluogo ed è iniziato il monitoraggio dell'area. I dati acquisiti hanno mostrato una sequenza di microterremoti che verosimilmente è stata innescata dai due eventi avvenuti il 22 gennaio. Sono stati individuati oltre 750 terremoti molto piccoli (M<2) di cui oltre 60 sono stati localizzati. Il 95% delle sorgenti localizzate ricade in un'area di circa 10 km2 e la profondità è inferiore a 3 km. Per circa 15 terremoti registrati da almeno 5 stazioni è stato possibile calcolare anche il meccanismo focale. I risultati indicano una dinamica distensiva nell'area epicentrale, tuttavia il quadro complessivo risulta piuttosto complesso, con meccanismi molto diversi per terremoti localizzati molto vicino tra loro.
Monitoraggio della sismicità locale nel Cilento nel periodo febbraio-ottobre 2014
LA ROCCA, MARIO;
2015-01-01
Abstract
Some temporary seismic stations were installed in Cilento from February to October 2014 for a monitoring of the local seismicity in the area of Roccadaspide and surrounding villages, where two earthquakes of magnitude Mw=3.6 and Mw=3.7 occurred on January 22, 2014. Following the warnings of rumbles and tremors from people living in the area, reported also by local press and television, a field survey was realized and the seismic monitoring begun. Acquired data showed a sequence of microearthquakes likely triggered by the two events occurred on January 22. We identified more than 750 very small earthquakes (M<2), of which more than 60 have been located. The 95% of the sources is located in an area of about 10 km2 with depth lower than 3 km. For about 15 earthquakes recorded by at least 5 stations we were able to compute also the focal mechanism. Results of our analysis suggest a predominant distensive dynamics in the epicentral area, although the full picture is rather complex, with significantly different mechanisms for sources very near to each other.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
