5000 + quakes in under 70 days

Most are aware of the quakes, but not the massive numbers....


Mogul and Verdi residents aren’t the only ones shaken up by an unpredictable swarm of earthquakes, which has also kept scientists guessing at the unusual increase in quake magnitude and irregular patterns.

Seismologists are struggling to guess whether the fault system of northwest Reno has a wild ride in store for residents or if it will just stop.
John Anderson, director of the seismological laboratory at the University of Nevada, Reno said some days with few quakes above a magnitude 2 would seem to suggest that the disturbances are petering out.
But the most powerful magnitude of a 4.7 occurred on April 25 after weeks of weaker temblors, which tends to defy historic patterns.
“Scientists all over are scratching their heads, and they are the West Coast’s finest,” said Glenn Biasi, associate research seismology professor at the University of Nevada, Reno.
Anderson said that several recent days with few quakes greater than a magnitude 2 could suggest the tremors are coming to an end, but the Mogul/Verdi quake series has stopped and started up before.
Since the swarm began, Anderson said, more than 600 quakes have been greater than magnitude 1 and more than 5,000 temblors have registered at some level.
On a chart tracking the cumulative number of northwest Reno earthquakes with stacking dots, Anderson hopes to see a flat line signifying the end of the series.
“It looks like it’s slowing down,” Anderson said. “It would be ideal if (the magnitude 1 quakes) leveled off before number 650.”
But Anderson said a future quake could top last Friday’s 4.7, which threw cans into store isles, cracked home walls and triggered a rock slide that broke a wooden flume carrying water to a Reno treatment plant.
The unusual behavior of the swarms rattling Mogul and Verdi for the past 66 days, has prompted experts to search the West Coast for similar cases.
Biasi said northwest Reno swarms have many similarities to a 46-day swarm of quakes that occurred in 1990 around San Ramon, Calif. The strongest quake in that sequence was 4.6, and the quakes gradually subsided.
Because Mogul and Verdi’s quakes are occurring in a site where there had been no previously mapped significant fault lines, there still is hope the temblors might simply stop without a large earthquake relieving the pressure generated by shifting land masses, Anderson said.