‘Swarmageddon’ of over 1,000 small earthquakes in less than a month sparks fresh fears of a megaquake in Southern California
- San Bernardino and Riverside counties have seen hundreds of quakes in 3 weeks
- Spike in small earthquakes can slightly raise chances of a larger one, experts say
- For now, however, scientists monitoring region say chances of big event are slim
A spate of small earthquakes in Southern California is giving seismologists yet another opportunity to remind residents that they must always be prepared for the next big event.
While small earthquakes magnitude 3 and under are almost a daily occurrence, a recent swarm has produced more than 1,000 temblors over the last three weeks, sparking fears that something more destructive may be on the way, according to the LA Times.
Experts thankfully say that’s likely not the case this time – but, they warn a big earthquake in the region is ultimately inevitable.
A spate of small earthquakes in Southern California is giving seismologists yet another opportunity to remind residents that they must always be prepared for the next big event. Small earthquakes across the state in recent weeks are plotted above
The swarm has given rise to hundreds of quakes throughout San Bernardino and Riverside counties in recent weeks, LA Times reports.
It’s reminiscent of activity near the San Andreas Fault three years ago that had some scientists on edge for a possible large triggered earthquake.
While that never happened, a spike in small earthquakes can raise the chances of a bigger event, albeit only slightly.
Scientists say people living in the earthquake-prone state
‘I would redefine normal as: you should still be prepared for a large earthquake,’ Andrew Llenos, a research geophysicist with the US Geological Survey, told the LA Times.
‘We do know a big earthquake is going to happen’ at some point in the future.
At the beginning of this year, Los Angeles released an earthquake warning app designed to give residents a precious few seconds to drop, cover and hold on in the event of a quake.
ShakeAlertLA became available for download on Android and Apple phones.
Based on a warning system developed by the U.S. Geological Survey, the app will alert users when there’s a quake of magnitude 5.0 or greater in the state.
Los Angeles recently released an earthquake warning app that could give LA County residents a few seconds’ heads up to take cover in the event of tremors
HOW ARE EARTHQUAKES MEASURED?
Earthquakes are detected by tracking the size, or magnitude, and intensity of the shock waves they produce, known as seismic waves.
The magnitude of an earthquake differs from its intensity.
The magnitude of an earthquake refers to the measurement of energy released where the earthquake originated.
Magnitude is calculated based on measurements on seismographs.
The intensity of an earthquake refers to how strong the shaking that is produced by the sensation is.
A 5.3 magnitude earthquake hit the Channel Islands off the coast of southern California on Thursday at 10.30am
According to the United States Geological Survey, ‘intensity is determined from the effects on people, human structures and the natural environment’.
Earthquakes originate below the surface of the earth in a region called the hypocenter.
During an earthquake, one part of a seismograph remains stationary and one part moves with the earth’s surface.
The earthquake is then measured by the difference in the positions of the still and moving parts of the seismograph.
Depending on where the quake hits, the app says the warning could arrive before, during or after the quake.
It urges people who see the alert or feel the shaking to take precautions to avoid injury, and could provide up to tens of seconds notice ahead of tremors in the area.
‘I actually think that we can say today that ShakeAlert is the most sophisticated earthquake early warning system in the world,’ said Richard Allen, director of UC Berkeley’s Seismological Laboratory following an earlier test of the system.
‘The challenge is getting that alert out to every single individual across the state of California or across the Pacific Northwest.
‘The reason is that the technology for delivering alerts to all 8 million residents of the Bay Area within a second does not exist today.’