Bulletin of the Seismological Society of America; February 2006; v. 96; no. 1;
p. 59-68; DOI: 10.1785/0120050108
© 2006 Seismological Society of America
Surface Deformation Associated with the Mw 6.4, 24 February 2004 Al Hoceima, Morocco, Earthquake Deduced from InSAR: Implications for the Active Tectonics along North Africa
Ziyadin Cakir1,
Mustapha Meghraoui1,
Ahmet M. Akoglu2,
Nasser Jabour3,
Samir Belabbes1 and
Lahsen Ait-Brahim4
1 EOSTInstitut de Physique du
Globe
5, rue René Descartes
67084 Strasbourg Cedex,
France
ziyadin.cakir{at}eost.u-strasbg.fr
(Z.C.,
M.M., S.B.)
2 Eurasian Institute of Earth Sciences
ITU
Istanbul, Turkey
(A.M.A.)
3 Laboratoire de
Geophysique
CNRST
Rabat, Morocco
(N.J.)
4 des Sciences de la
Terre
Universite Mohammed V
Morocco
(L.A.-B.)
We study the surface deformation associated with the 24 February 2004 Al
Hoceima earthquake (Mw 6.4) that recently affected the Rif
Mountains of Morocco. The coseismic displacement field is mapped using synthetic
aperture radar interferometry (InSAR) with the Envisat (ESA)
satellite data acquired in the ascending and descending modes. Our analysis and
modeling of InSAR data suggest that the earthquake is associated with a
northwestsoutheast-trending right-lateral, apparently blind strike-slip
fault with a seismic moment reaching 6.8 x 1018 N m. This
result is in contrast with the north-northeastsouth-southwest
left-lateral fault mechanism inferred from the modeling of seismic waves.
Thrust-and-fold structures of the Rif Mountains developed during the Tertiary
period, but the recent significant seismic events and late-Quaternary
deformation indicate eastwest extension accommodated by
northsouth-trending normal and northwestsoutheast- and
northeast southwest-trending conjugate strike-slip faults. The active
deformation illustrates the fragmentation of the Rif Mountain range due to the
AfricaIberia collision and west- southwestward escape tectonics.
Copyright © 2009 by Seismological Society of America