TY - JOUR
T1 - Active faulting offshore SE Spain (Alboran Sea)
T2 - Implications for earthquake hazard assessment in the Southern Iberian Margin
AU - Gràcia, Eulàlia
AU - Pallàs, Raimon
AU - Soto, Juan Ignacio
AU - Comas, Menchu
AU - Moreno, Ximena
AU - Masana, Eulàlia
AU - Santanach, Pere
AU - Diez, Susana
AU - García, Margarita
AU - Dañobeitia, Juanjo
AU - Bartolomé, R.
AU - Farrán, M.
AU - Gómez, M.
AU - Alpiste, M. J.R.
AU - Lastras, G.
AU - Wilmott, V.
AU - Perea, H.
AU - Blondel, P.
AU - Gómez, O.
AU - Bullock, L.
AU - Jacobs, C.
AU - Rouse, I.
AU - White, D.
AU - Whittle, S.
AU - Terrinha, P.
AU - Gafeira, J.
AU - Roque, C.
PY - 2006/1/31
Y1 - 2006/1/31
N2 - The southern margin of the Iberian Peninsula hosts the convergent boundary between the European and African Plates. The area is characterised by low to moderate magnitude shallow earthquakes, although large historical events have also occurred. In order to determine the possible sources of these events, we recently acquired swath-bathymetry, TOBI sidescan sonar and high-resolution seismic data on the Almería Margin (Eastern Alboran Sea). The new dataset reveals the offshore continuation of the NE-SW trending Carboneras Fault, a master fault in the Eastern Betic Shear Zone, and its associated structures (N150 and NS faults). These structures are active since they cut the Late Quaternary sedimentary units. The submarine Carboneras Fault zone is 100 km long, 5-10 km wide, and is divided into two N045 and N060 segments separated by an underlapping restraining stepover. Geomorphic features typically found in subaerial strike-slip faults, such as deflected drainage, water gaps, shutter ridges, pressure ridges and "en echelon" folds suggest a strike-slip motion combined with a vertical component along the submarine Carboneras Fault. Considering the NNW-SSE regional shortening axis, a left-lateral movement is deduced for the Carboneras Fault, whereas right-lateral and normal components are suggested for the associated N150 and NS faults, respectively. The offshore portion of this fault is at least twice as long as its onshore portion and together they constitute one of the longest structures in the southeastern Iberian Margin. Despite the fact that present day seismicity in the Almería margin seems to be associated with the N150 to NS faults, the Carboneras Fault is a potential source of large magnitude (Mw ∼7.2) events. Hence, the Carboneras Fault zone could pose a significant earthquake and tsunami hazard to the coasts of Spain and North Africa, and should therefore be considered in any hazard re-evaluation.
AB - The southern margin of the Iberian Peninsula hosts the convergent boundary between the European and African Plates. The area is characterised by low to moderate magnitude shallow earthquakes, although large historical events have also occurred. In order to determine the possible sources of these events, we recently acquired swath-bathymetry, TOBI sidescan sonar and high-resolution seismic data on the Almería Margin (Eastern Alboran Sea). The new dataset reveals the offshore continuation of the NE-SW trending Carboneras Fault, a master fault in the Eastern Betic Shear Zone, and its associated structures (N150 and NS faults). These structures are active since they cut the Late Quaternary sedimentary units. The submarine Carboneras Fault zone is 100 km long, 5-10 km wide, and is divided into two N045 and N060 segments separated by an underlapping restraining stepover. Geomorphic features typically found in subaerial strike-slip faults, such as deflected drainage, water gaps, shutter ridges, pressure ridges and "en echelon" folds suggest a strike-slip motion combined with a vertical component along the submarine Carboneras Fault. Considering the NNW-SSE regional shortening axis, a left-lateral movement is deduced for the Carboneras Fault, whereas right-lateral and normal components are suggested for the associated N150 and NS faults, respectively. The offshore portion of this fault is at least twice as long as its onshore portion and together they constitute one of the longest structures in the southeastern Iberian Margin. Despite the fact that present day seismicity in the Almería margin seems to be associated with the N150 to NS faults, the Carboneras Fault is a potential source of large magnitude (Mw ∼7.2) events. Hence, the Carboneras Fault zone could pose a significant earthquake and tsunami hazard to the coasts of Spain and North Africa, and should therefore be considered in any hazard re-evaluation.
KW - Alboran Sea
KW - Carboneras Fault zone
KW - Seismicity
KW - Strike-slip faulting
KW - Submarine channels
UR - http://www.scopus.com/inward/record.url?scp=30844453844&partnerID=8YFLogxK
U2 - 10.1016/j.epsl.2005.11.009
DO - 10.1016/j.epsl.2005.11.009
M3 - Article
AN - SCOPUS:30844453844
SN - 0012-821X
VL - 241
SP - 734
EP - 749
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
IS - 3-4
ER -