Seafloor Margin Map Helps in Understanding Subduction Earthquakes

J.-Y. Collot (1) , S. Migeon (1) , G. Spence (1) , Y. Le Gonidec (1) , B. Marcaillou (1) , J.-L. Schneider (1) , F. Michaud (1) , A. Alvarado (1) , Jean-Frédéric Lebrun (1) , M. Sosson (1) , A. Pazmino (1)

1 GEOAZUR 6526 - Géoazur

Ecuador and southwest (SW) Colombia suffered widespread damage during the twentieth century as a result of some of the greatest subduction earthquakes and associated tsunamis ever recorded. In 1906, the Ecuador-SW Columbia margin, located at the transition between the continent and deep ocean, ruptured over a 500-kilometer length as a single great (Mw = 8.8) subduction earthquake (Figure 1a) [Kelleher, 1972]. The 1906 rupture zone was partially reactivated in 1942, 1958, and 1979 by earthquakes of Mw 7.7 to 8.2 (Figure 1b), with 100–200 kilometer long rupture zones [Beck and Ruff, 1984]. Such considerable variation in earthquake rupture length and magnitude in this area-s seismic cycles during the last century has raised questions about the nature and enduring significance of the boundaries that exist between rupture zones and about the long-term recurrence interval between earthquakes.

Domaines: Sciences de la Terre

J.-Y. Collot, S. Migeon, G. Spence, Y. Le Gonidec, B. Marcaillou, et al.. Seafloor Margin Map Helps in Understanding Subduction Earthquakes. Eos, Transactions American Geophysical Union, 2005, 86 (46), pp.463-465. ⟨10.1029/2005EO460003⟩. ⟨hal-00453741⟩