© ESAThe Strait of Gibraltar, which lies between the southern coast of Spain and the northern coast of Morocco, is the only place where water from the Atlantic Ocean mixes with water from the Mediterranean Sea.
More than 250 years later, geologists are still piecing together the tectonic story behind that powerful earthquake. A unique subduction zone beneath Gibraltar, the southernmost tip of the Iberian Peninsula, now seems to be culprit. Subduction zones are the spots where one of Earth's tectonic plates dives beneath another, often producing some of the world's strongest earthquakes.
"At a global scale, subduction is the only process that produces magnitude-8 or -9 earthquakes," said Marc-Andre Gutscher, a geologist at the University of Brest in France. "If subduction occurred, and is still occurring here, then it's highly relevant to understanding the region's seismic hazards."
