Earthquakes Rattle California, Largest In 34 Years Hits Yellowstone
Lawrence LeBlond for redOrbit.com – Your Universe Online
As many as 30 earthquakes were recorded in California over the past 24 hours, most of which were less than a magnitude in intensity. Despite all the tremors regional seismometers pick up in California and Nevada — 808 in the past week alone — most go unnoticed by residents.
The lack of a significant earthquake in the region also poses a problem to emergency management officials, who want Californians to be prepared for the next “big one.” Because no major temblor has struck Southern California in 20 years, most people do not seem to feel earthquake preparedness is important.
The powerful 6.7 magnitude Northridge earthquake that struck in 1994 killed 67 people; in 1997, a 5+ magnitude hit the West Coast and since then it has remained relatively quiet – so quiet that many CA residents may have become lax in efforts to prepare for disaster. However, it now seems like earthquake activity is once again picking up in intensity.
“The last 17 years has been the quietest time we have ever seen,” Lucile M. Jones, a seismologist at the United States Geological Survey, said in an interview with the NY Times. “Maybe we’re starting to turn back to more normal levels.”
Late last week two back-to-back earthquakes shook Los Angeles. The first was relatively small at 3.6 magnitude, but a second long and rolling 5.1 temblor rocked the region; these were followed by no less than 175 aftershocks over the weekend. And these quakes come nearly two weeks after a 4.4 magnitude event woke Los Angeleans from slumber.
While none of these quakes caused any injuries or widespread damage, geologists see them as “the predictable end of a cycle: a return to what might be an uncomfortable normal in which 5-magnitude earthquakes become routine events.”
If this is the case, then it may be a good time for emergency management officials to begin getting Los Angeleans prepared for another destructive earthquake. A growing amount of criticism has been geared toward Los Angeles for not being prepared to minimize earthquake casualties. In an effort to bring awareness and preparedness back to full scale there, LA mayor Eric Garcetti appointed Jones as a special adviser to draw up an earthquake preparedness plan, following the lead of San Francisco and other West Coast cities.
According to Garcetti and Jones, the biggest obstacle in pushing the city to take crucial steps is the lack of a sense of urgency as a result of the long lapse in significant seismic activity.
“When earthquakes happen that are big enough to feel but small enough not to cause great damage, they help us provide the awareness we need in Southern California,” Garcetti told NY Times’ Adam Nagourney on Sunday. “It’s what everybody is talking about. The place is abuzz about earthquakes. I’m going to take that and use that for our efforts.”
Apart from a lack of preparedness, Jones noted three serious shortcomings in the city’s earthquake preparedness plan. The first is hundreds of old concrete buildings that are at risk of damage from serious temblors. The second is lack of a plan for catastrophic collapse in water supply and thirdly a lack of communication. Currently, many of the aqueducts and telecommunications cables that connect to Los Angeles cross the San Andreas Fault.
Jones noted that the absence of severe geological activity in the region over the past 17 years largely accounts for the lull in earthquake readiness. She thinks that the recent series of temblors would make it easier to rally political support for measures like those that force owners to rehabilitate their outdated buildings.
“When you have damage, it’s a lot easier to talk to people about what you need to do to avoid damage,” she said. “There are real lives at stake. We absolutely know that there are buildings that will kill people when they collapse.”
The biggest earthquake to hit Yellowstone National Park in more than 34 years struck Sunday, delivering a 4.8 magnitude jolt to the region, but leaving no damage and causing no immediate injuries.
The tremor, which is considered relatively light by seismic standards, struck the northwest corner of the park on Sunday, following a series of smaller tremors that shook the area since Thursday, according to geologists at the University of Utah Seismograph Stations.
The quake struck at 6:34 a.m. near the Norris Geyser Basin and was felt in two small Montana towns up to 23 miles away.
With the flurry of activity occurring at Yellowstone, geologists from the USGS planned to tour the park to determine if Sunday’s quake altered any of Yellowstone’s geothermal features, including geysers, mud pots and hot springs.
Yellowstone is no stranger to earthquake activity. While not experiencing them on the magnitude that California does (avg. 10,000 per year), the park does get about 1,000 to 3,000 tremors annually, according to information from the Yellowstone Volcano Observatory.
Speaking of volcanoes, Yellowstone of course sits atop the Yellowstone caldera, an ancient supervolcano that many scientists feel is on the verge of another super-eruption. The caldera has unleashed its fury on at least two other dates over the past few million years: one about 2.1 million years ago, a second around 1.3 million years ago, and a third around 640,000 years ago. The math suggests a fourth super-eruption is upon us.
While the caldera has recently been discovered to be as much as 2.5 times bigger than previously estimated, some experts have said the caldera is on the verge of extinction, if it hasn’t died out yet.
A recent study by Ken Sims, of the University of Wyoming, suggests that Yellowstone could soon be dead, based on a survey of the gas, water and air samples around the park, as reported by the Daily Mail.
To be clear, Sunday’s quake also points to evidence, or lack thereof, that Yellowstone is on the verge of an eruption.
The quake occurred near the center of an area of the ground uplift that geologists have been studying for the past several months, University of Utah scientists said in a statement to Reuters. The elevated seismic activity was also found in the area during a previous period of uplift from 1996 to 2003.
The recent series of temblors in the park is linked to this uplift, which in turn is caused by the upward movement of molten rock beneath the crust, according to the USGS.
The experts said there is no indication that the seismic activity is linked to an impending eruption of the Yellowstone caldera. Researchers with the observatory have maintained that catastrophic super-eruptions are unlikely over the next tens of thousands of years, but less extreme lava releases may occur within thousands of years.
If anything, the molten rock underneath the park fuels Yellowstone’s famous geothermal features, such as Old Faithful.
Image Below: Data of recent series of earthquakes to hit California and Nevada. Credit: Southern California Earthquake Data Center