The
southern California surge channel continues to display earthquakes
borne of
internal lava movement. Was the M5.4 tremor an aftershock of the M7.2
Easter quake? The USGS doesn't think so. Instead, seismologists are
focusing on the San Jacinto fault, the
most active earthquake fault in southern California, extending for more
than 100 miles from the international border into San Bernardino and
Riverside, a major metropolitan area often called the Inland Empire.
The Daily Breeze
The magnitude-5.4 earthquake centered in San Diego County shook
buildings across the Southland today, but there were no immediate
reports of damage or injuries in the Los Angeles area.
According to the U.S. Geological Survey's Kate Hutton, the quake struck
at 4:53 p.m., and it was centered 13 miles north-northwest of Borrego
Springs in San Diego County.
The temblor was felt strongly in downtown San Diego, and it rattled
buildings in the Coachella Valley in Riverside County. It also rattled
buildings in West Los Angeles, West Hills and Hollywood.
Officials at Los Angeles International Airport said the airport was
operating normally, with no reported flight disruptions. The Los
Angeles Department of Water and Power reported that it had no impacts
from the quake, and no known disruptions in water and power service.
Southern California Edison also reported no outages.
Metrolink train service was also unaffected.
USGS seismologist Hutton told reporters at Caltech in Pasadena that the
quake likely occurred in the San Jacinto fault zone, and it was
followed by about two dozen small aftershocks, the largest a
magnitude-3.6.
She said the quake was likely not an aftershock to the magnitude-7.2
temblor centered near the Mexican border that rattled much of Southern
California in early April.
"This earthquake, probably, although it's pretty close in time after
the April earthquake, it's probably not an aftershock because it's
located in a different location," Hutton said. "But it probably is what
we would call a triggered earthquake, because we're now thinking that
the 7.2 earthquake in April changed the strain slightly in the San
Jacinto fault area and the Elsinore fault area, and it increased the
number of small earthquakes that were happening there. And this is an
example of an earthquake that's like that."
Hutton said residents should take today's quake as a warning to be
prepared for temblors.
"The best way for people to look at this earthquake is that it's a
drill," she said. "... If this one had been the big one, what would I
have done? Would I have been prepared? Would I have had my supplies, my
plan and all that? ... So review everything, check your kit, because we
can't predict earthquakes, we don't know when they're going to happen,
so we have to be prepared all the time. The USGS has
released the following tectonic summary of the M5.4 earthquake. |
