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A series of earthquakes, the largest 6.2 which occurred 2
days ago at a depth of 10km close to Los Mochis, has shaken the ocean floor in the
Sea of Cortez.
The effects should have been far enough away to have been
missed in Los Cabos however given the total number (6 tremors in 3 days) some
effects may have been felt.
Los Cabos has
a history of earthquakes, some of them relatively severe, with one actually
occurring in the middle of Hurricane Odile.
The reason for this is that the Baja California peninsula was once
a part of the North American Plate, the tectonic plate of which mainland Mexico
remains a part. About 12 to 15 million years ago the East Pacific Rise began
cutting into the margin of the North American Plate, initiating the separation
of the peninsula from it. Spreading within the Gulf of California there are
short oblique rifts or ridge segments connected by long northwest trending
transform faults, which together comprise the Gulf of California Rift Zone.
The north end of the rift zone is located in the Brawley seismic
zone in the Salton Sea basin between the Cerro Prieto Fault and the San Andreas
Fault.
The Baja California peninsula is now part of the Pacific Plate and
is moving with it away from the East Pacific Rise in a north northwestward
direction and it is this pressure and tension which gives rise to the
earthquakes in the area from time to time.