Seafloor Margin Map Helps in Understanding Subduction Earthquakes

Description

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.

Abstract

International audience

Additional details