The Tripoli, Libya, Earthquake of September 4, 1974: Implications for the active tectonics of the central Mediterranean

摘要: Source parameters have been determined for the earthquake (Ms 5.6) that occurred offshore of Tripoli, Libya, on September 4, 1974. One nodal plane its focal mechanism has dip 37°, strike 297°, and rake −141°, indicating oblique normal faulting. This is subparallel to many west-northwest striking faults in epicentral area most likely fault plane, a component right-lateral strike-slip with slip vector azimuth N84°E. Inversion long-period teleseismic body waves indicates 12-km centroid depth 0.4 × 1018 N m seismic moment. A much larger 7.0) April 19, 1935, same zone active ∼400 km farther southeast near Sirte probably involved similar sense. zone, which name “Tunisia-Libya zone” appears appropriate, overall northwest-southeast extent ∼1000 from northern Libya between Tunisia Sicily. It takes up change motion direction relative stable Europe west north inside African plate N30°E N50°E Ionian Sea Sicily, southernmost peninsular Italy, southwest Greece, Libya. suggested Sicily agrees independent estimates rates senses elsewhere Italy.