The 2003 Boumerdes, Algeria Earthquake: Regional Moment Tensor Analysis

Document Type


Publication Date


Digital Object Identifier (DOI)



We used regional broadband seismograms to determine seismic moment tensors for the destructive May 21, 2003 Boumerdes (Algeria) Mw = 7.0 earthquake and its larger aftershocks. Fully automatic inversions using near-real time data provided solutions for seven Mw ≥ 4.7 events within 90 minutes after event occurrence. After adding off-line data, we manually obtained 30 solutions (Mw ≥ 3.8) from May 2003 to January 2004. All have shallow source depths (6–21 km). The median P-axis orientation (338°) of 24 thrust and four strike-slip events is consistent with Africa-Eurasia plate motion (330°). The main shock hypocenter at 8–10 km depth at the coastline and its shallow southward dip (25° ± 5°) puts the fault surface trace 15–20 km offshore, consistent with documented seafloor deformation at the base of the continental slope. A main shock rupture length of about 50 km is deduced from first day aftershocks and location of strike-slip events. The strike-slip events probably define the western rupture end and indicate a left-step of main convergence. Fault strike variability of thrust events suggests fault orientation changes and possibly fault segmentation.

Was this content written or created while at USF?


Citation / Publisher Attribution

Geophysical Research Letters, v. 32, issue 6, art. L06305