Acoustic and seismic imaging of the Adra Fault (NE Alboran Sea): in search of the source of the 1910 Adra earthquake

作者：Gracia E^*; Bartolome R; Lo Iacono C; Moreno X; Stich D; Martinez Diaz J J; Bozzano G; Martinez Loriente S; Perea H; Diez S; Masana E; Danobeitia J J; Tello O; Sanz J L; Carreno E

来源：Natural Hazards and Earth System Sciences, 2012, 12(11): 3255-3267.

DOI：10.5194/nhess-12-3255-2012

Recently acquired swath-bathymetry data and high-resolution seismic reflection profiles offshore Adra (Almeria, Spain) reveal the surficial expression of a NW-SE trending 20 km-long fault, which we termed the Adra Fault. Seismic imaging across the structure depicts a sub-vertical fault reaching the seafloor surface and slightly dipping to the NE showing an along-axis structural variability. Our new data suggest normal displacement of the uppermost units with probably a lateral component. Radiocarbon dating of a gravity core located in the area indicates that seafloor sediments are of Holocene age, suggesting present-day tectonic activity. The NE Alboran Sea area is characterized by significant low-magnitude earthquakes and by historical records of moderate magnitude, such as the M-w = 6.1 1910 Adra Earthquake. The location, dimension and kinematics of the Adra Fault agree with the fault solution and magnitude of the 1910 Adra Earthquake, whose moment tensor analysis indicates normal-dextral motion. The fault seismic parameters indicate that the Adra Fault is a potential source of large magnitude (M-w %26lt;= 6.5) earthquakes, which represents an unreported seismic hazard for the neighbouring coastal areas.

• 出版日期2012