Global Earthquake Watch

[lurkey]

All-inclusive thread for global earthquake reports

Starting off with reports of a swarm of earthquakes reported off of Oregon.

Swarm of Earthquakes Detected Off Oregon
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Apr 11, 9:04 PM (ET)

By JEFF BARNARD


GRANTS PASS, Ore. (AP) - Scientists listening to underwater microphones have detected an unusual swarm of earthquakes off the central Oregon Coast.

Scientists don't know what the earthquakes mean, but they could be the result of magma rumbling underneath the Juan de Fuca Plate - away from the recognized earthquake faults off Oregon, said geophysicist Robert Dziak of the National Oceanic and Atmospheric Administration and Oregon State University's Hatfield Marine Science Center in Newport, Ore.

They hope to send out the OSU research ship, Wecoma, to take water samples, looking for evidence that sediment on the ocean bottom has been stirred up and chemicals in the water that would indicate magma is moving up through the crust, Dziak said.

There have been more than 600 quakes over the past 10 days in a basin 150 miles southwest of Newport. The biggest was magnitude 5.4 and two others were more than magnitude 5.0, OSU reported. They have not followed the typical pattern of a major shock followed by a series of diminishing aftershocks, and few have been strong enough to be felt on shore.

It looks like what happens before a volcanic eruption, except there are no volcanoes in the area, Dziak said.

The Earth's crust is made up of plates that rest on molten rock, which are rubbing together side to side and up and down. When the molten rock, or magma, erupts through the crust it creates volcanoes. That can happen in the middle of a plate. When the plates lurch against each other, they create earthquakes along the edges of the plates.

In this case, the Juan de Fuca Plate is a small piece of crust being crushed between the Pacific Plate and North America, Dziak said.

On the hydrophones, the quakes sound like low rumbling thunder and are unlike anything scientists have heard in 17 years of listening, Dziak said. Some of the quakes have also been detected by earthquake instruments on land.

The hydrophones are leftover from a network the Navy used to listen for submarines during the Cold War. They routinely detect passing ships, earthquakes on the ocean bottom and whales calling to each other.

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Major quake almost inevitable for California

By Dan Whitcomb

LOS ANGELES (Reuters) - California will almost inevitably be struck by a major earthquake, and possibly a catastrophic quake, sometime in the next 30 years, scientists said on Monday in the most comprehensive geologic forecast for the state.

California faces a more than 99 percent chance of being hit by a magnitude 6.7 temblor -- the size of the 1994 Northridge quake -- in the next 30 years, according to a study using new data and analyzing earthquake probabilities across the state.

The analysis found a nearly 50 percent chance that California would be rocked by a magnitude 7.5 quake, which is capable of inflicting catastrophic damage if it is centered under a big city like Los Angeles or San Francisco.

"We can expect that we're going to get hammered by a big earthquake and we'd better be prepared," said Tom Jordan, director of the Southern California Earthquake Center at the University of Southern California.

"Magnitude 7.5, that's a really big earthquake," Jordan said. "If that were to hit on the San Andreas Fault it could be very destructive. You're talking about an earthquake that might span 200 miles of fault length and a displacement of 12 feet or more.

"If that were to take place in say, the Los Angeles region, then you would have a big problem," he said.

Jordan said the chance of a 7.5 magnitude quake hitting Southern California was 37 percent, compared to 15 percent in Northern California, largely because the 1906 San Francisco earthquake relieved stress from the San Andreas Fault there.

The 1906 San Francisco quake was thought to have been a magnitude of around 7.8 or higher. The last temblor of that size in Southern California was in 1857, and the southernmost section of the San Andreas Fault has not seen such an event since 1680.

"Those faults have been accumulating stress all this time and that makes large earthquakes highly probable," Jordan said.

The January 17, 1994, Northridge quake in Los Angeles killed 72 people, injured more than 10,000 and caused billions of dollars in damage.

The study was conducted by the U.S. Geological Survey, the Southern California Earthquake Center and California Geological Survey and is significant because it presents the probabilities statewide for the first time.

"This is the most comprehensive earthquake forecast ever for the state of California," Jordan said, adding that it was requested by the California Earthquake Authority and would be used by the agency as a basis for setting insurance rates.

(Editing by Bob Tourtellotte)

[RL3AO]

LOS ANGELES (Reuters) - California will almost inevitably be struck by a major earthquake, and possibly a catastrophic quake, sometime in the next 30 years, scientists said on Monday in the most comprehensive geologic forecast for the state.

Way to go out on a limb on that one.

[lurkey]

Magnitude 5.4Illinois

Earthquake Strikes Downstate, Tremors In Chicago
No Reports Of Injuries Or Damage In Chicago, But Plenty Of Curiosity, Panic
CHICAGO (CBS) ― An earthquake with a magnitude of 5.4 struck in southern Illinois early Friday, and was felt throughout the Chicago area.

There were no injuries or structural damage reported in Northern Illinois, but many people were curious and even panicked.

The U.S. Geological Survey said the earthquake struck with an epicenter about seven miles from downstate Mt.Carmel, and about 66 miles from Evansville, Ind., at 4:36:57 a.m.

The quake was also felt as far away as Ohio and Kentucky, and residents were unaccustomed to such a large temblor in the Midwest.

West Salem is in Edwards County in Southern Illinois, and dispatcher Lucas Griswold says the sheriff's department received several calls about the earthquake but only reports of minor damage and no injuries.

The tremor was felt throughout Chicago and Northern Illinois, including in the CBS 2 studios at 630 N. McClurg Ct. Audiovisual equipment and other items shook as the staff prepared for the news, and many of the staff reported the building shook.

Stephen, our front desk security guard at CBS 2, felt the earthquake while at work.

"I was sitting at the shipping dock at the time, and the chair began to sway very, very slightly. I thought I was having muscle spasms," he said. He has worked in the building for 25 years, and said he has never felt anything like it.

CBS 2 Executive Producer of Digital Media John Dodge said between 4:30 and 5 a.m., he was awoken by a rattling sound in his house in Northwest Indiana.


Fire Department spokesman Larry Langford said the Fire Department had not been sent out on any emergency calls, but there was a spike in calls to 911 at 4:40 a.m.

"The tremor was very short, and from the information we're getting now, we had no significant damage in Chicago that we've been able to ascertain as yet, and no significant injuries either," Langford said.

A city Office of Emergency Management and Communications staffer named Jennifer said the department has received several calls.

"Earlier this morning, we received several calls to the 911 Center with reports of the earth shaking. No reports of damage this time. We want to remind residents to stay calm," Jennifer said. "If you have an emergency, call 911, but if you're looking for information, call 311."

She said the office is working with local and state partners to assess and monitor the situation.

Illinois Department of Transportation spokesman Mike Claffey says Chicago area roadways haven't been affected.

Timothy Macaskill said the quake woke him up in his Chicago high-rise. He felt his bed "swaying back and forth and I heard some furniture in my living room creak. A little weird to feel this all the way up on the 18th floor of a high-rise.''

Tom Perry of Crown Point, Ind., said everything shook as he was up working.

"I'm an attorney, and I was up working on some cases, and we felt lateral shifting, and it lasted about 10 seconds," Perry said. "We had some things hanging that were shifting back and forth…. We don't have any structural damage."

Maria of Bourbonnais said her house shook in a terrifying tremor.

"I was actually up early with my husband going to work, and I was on the computer, and the birds were chirping outside, the windows were open, and all of a sudden I heard this rumbling. First I heard my dog pacing downstairs, which is unusual for a little dog, and then everything started shaking – this rumbling noise – and I have a chandelier on the wall that has crystals hanging from it," she said. "It was a good five seconds, I would say. It was unusual."

"About 4:40 a.m. I woke up to a rattling sound of something tapping on metal. My boyfriend next to me woke up right after I did and we were asking each other what this noise was. We both thought it was the other tapping on the bed," wrote Rebecca Garcia. "We picked our heads up and listened to it to see if we could see where it was coming from and it was definitely about ten seconds later when we finally seen the metal night stand with a necklace dangling and hitting against it after that the whole attic ceiling and walls where we were sleeping started off slowly swaying and quickly started to shake faster and faster and then it just stopped.

"First thought I had was that we were having a earthquake and we both thought it was going to cave in. It sure did look like it was. We both jumped up ran downstairs and everything was fine. My mom also woke up from the sound of her wall mirror shaking. It seemed at that moment everything was silent," Garcia continued. "We heard nothing but the shaking of the walls. Even the birds chirping seemed to have disappeared. Dog was silent and sleeping. It was the weirdest and scariest feeling ever. So many things were going through my mind in this little amount of time."

This morning around 4:30 am I noticed the birds stopped chirping outside my window. Within 5 minutes or so I heard change in a dish rattling. The rattling increased and decreased for over 30 seconds at which point it stopped and the birds started chirping again. My wife and I sleep on the second floor and could feel some swaying. It definitely lasted on and off for at least 30 seconds. No damage but pictures in the house were tilted.

In Mount Carmel, 15 southeast of the epicenter, a woman was trapped in her home by a collapsed porch but was quickly freed and wasn't hurt, said Mickie Smith, a dispatcher at the police department.

Phones started ringing at the Crawford County Sheriff's Department in Robinson, about 15 miles north of the epicenter, but there were no immediate reports of damage, dispatcher Marsha Craven said.

"They didn't know if it was the refinery blowing up or an earthquake," she said, referring to the a local petroleum refinery.

Craven said she's lived in the area her whole life, and felt a handful of earthquakes, but couldn't recall one this big.

In Cincinnati, one woman said she felt something that lasted for up to 20 seconds.

"All of a sudden, I was awakened by this rumbling shaking," said Irvetta McMurtry, 43. "My bed is an older wood frame bed, so the bed started to creak and shake, and it was almost like somebody was taking my mattress and moving it back and forth."

The quake was also felt as far away as Murfreesboro, Tenn., where Allyson Coen provided this report:

"I just got home from work and was winding down when everything in my living room began to shake," she wrote to CBS 2. "Nothing fell but it was all moved around a bit. My poor cat was scared to death!"

The New Madrid Fault is the largest center for seismic activity in the area, and it is suspected if the New Madrid Fault was origin of the earthquake.

CBS 2's Mary Kay Kleist reported the most recent severe earthquake in the area hit in 1968. That earthquake was slightly less severe than this one, with a magnitude of 5.3.

In 1990, scientist Iben Browning said the New Madrid fault line was due for a catastrophic earthquake, but that never happened.

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Earth Gives Off Mysterious Low Hum
Friday, April 18, 2008

By Charles Q. Choi

Earth gives off a relentless hum of countless notes completely imperceptible to the human ear, like a giant, exceptionally quiet symphony, but the origin of this sound remains a mystery.

Now unexpected powerful tunes have been discovered in this hum. These new findings could shed light on the source of this enigma.

The planet emanates a constant rumble far below the limits of human hearing, even when the ground isn't shaking from an earthquake. (It does not cause the ringing in the ear linked with tinnitus.)

This sound, first discovered a decade ago, is one that only scientific instruments — seismometers — can detect. Researchers call it Earth's hum.

Investigators suspect this murmur could originate from the churning ocean, or perhaps the roiling atmosphere.

Different types

In the past, the oscillations that researchers found made up this hum were "spheroidal" — they basically involved patches of rock moving up and down, albeit near undetectably.

Now oscillations have been discovered making up the hum that, oddly, are shaped roughly like rings.

Imagine, if you will, rumbles that twist in circles in rock across the upper echelons of the planet, almost like dozens of lazy hurricanes.

Scientists had actually expected to find these kinds of oscillations, but these new ring-like waves are surprisingly about as powerful as the spheroidal ones are. The expectation was they would be relatively insignificant.

New thinking

This discovery should force researchers to significantly rethink what causes Earth's hum.

While the spheroidal oscillations might be caused by forces squeezing down on the planet — say, pressure from ocean or atmospheric waves — the twisting ring-like phenomena might be caused by forces shearing across the world's surface, from the oceans, atmosphere or possibly even the sun.

Future investigations of this part of the hum will prove challenging, as "this is a very small signal that is hard to measure, and the excitation is probably due to multiple interactions in a complex system," said researcher Rudolf Widmer-Schnidrig, a geoscientist at the University of Stuttgart, Germany.

Still, a better understanding of this sound will shed light on how the land, sea and air all interact, he added.

Widmer-Schnidrig and fellow researcher Dieter Kurrle detailed their findings March 20 in the journal Geophysical Research Letters.

[lurkey]

Scientists: Even Bigger Quake Could Hit Midwest



The magnitude 5.2 earthquake that rocked the Midwest on Friday was felt from Kansas to Georgia.

Aftershocks could continue for months at this strange seismic zone at the nation's center and even trigger another big quake, a geophysicist said.

The quake occurred on a northern extension of the New Madrid fault, about 6 miles north of Mt. Carmel, Ill.

The New Madrid fault was responsible for devastating quakes in the Mississippi Valley in 1811 and 1812.

With that in mind, the Friday quake and its aftershocks may be raising the blood pressure of some residents and scientists.

For decades, scientists have debated whether and when the underlying fault could generate another temblor of similar and deadly strength.

"I think we saw a window to this possibility today in the Wabash Valley," said geophysicist Allessandro Forte of the Université du Québec à Montréal, who has studied the region's seismicity.

"It's to the north of the New Madrid seismic zone, but given the strength of crust, the stress can be distributed great distances," he said. "It's not clear if we could see something in the next few years or even next few months, I would say."

The last earthquake in the region to approach the severity of Friday's temblor was a 5.0 magnitude quake that shook a nearby area in 2002, according to the U.S. Geological Survey.

An event actually surpassing today's magnitude last occurred in 1968, a magnitude 5.3 quake that was felt in 23 states and in Ontario and Boston, said Forte.

The magnitude scale is logarithmic so a change of 0.1 or 0.2 makes a big difference in terms of energy output.

"The $64,000 question is what this earthquake portends for the future," Forte said. "The answer is I'm afraid it can go either way."

Stress relief or hair trigger?

One scenario predicts that some stress is relieved on the local faults where this earthquake occurred and will cool things down for a few decades. The other scenario is not so happy.

"There is the possibility, and we can only see over next few months what will happen, that the redistribution of stress on neighboring faults might trigger further earthquakes, and we can only guess as to whether they'll be equally large as today's earthquake," Forte said.

Aftershocks from the Friday quake will continue for several weeks, maybe months, he said. Already, there have been many, of magnitudes in the range of 2 and 3, radiating outward from the epicenter.

"If we are seeing a propagation outward of stress changes after today's 5.2, which was a big one, and those stress changes finally come up on a fault which is on a hair trigger and ready to go, those small changes are sufficient to generate another big one on a fault which is locked and ready to go," Forte said.

How much risk?

Recent estimates have downgraded the risk of a large earthquake on the New Madrid fault.

In the 1980s, scientists said there was a 90 percent chance of a magnitude 6 or 7 temblor occurring in this area within the next 50 years.

A 2007 USGS fact sheet, however, said there is only a 25 percent to 40 percent chance of a magnitude 6 or larger there in the next 50 years.

However, a team that includes Michael Ellis of the University of Memphis estimated in 2005 that the odds of another 8.0 event in the region within 50 years are between 7 and 10 percent.

These debates about the New Madrid fault are far from resolved, Forte said, with some saying the accumulated stress in area faults is weakening while others say it is not going to dissipate any time soon.

"This is not exactly a well-defined science as yet," he said.

Forte is pessimistic, based on his research on an ancient, giant slab of Earth called the Farallon slab that started its descent under the West Coast 70 million years ago.

According to one theory, the Farallon slab is now is causing mayhem and deep mantle flow 360 miles beneath the Mississippi Valley, where it effectively pulls the crust down an entire kilometer (.62 miles).

[The other, not necessarily contradictory theory is that the lower Mississippi Valley is the site of a failed rift, a crack that appeared in the North American tectonic plate hundreds of millions of years ago and never fully healed.]

"The stresses from the sinking Farallon slab are not going to disappear any time soon," he said.

J. David Rogers agrees. The geological engineer at Missouri University of Science and Technology says Midwestern earthquakes are potentially more powerful than California quakes.

Shakier situation

Unique geology in the Midwest increases the shaking intensity of earthquakes because seismic energy moves through the dense bedrock at very high speeds, then becomes trapped in soft sediments filling river channels and valleys, Rogers said.

Rogers and some of his graduate students have been modeling synthetic seismic events in the New Madrid region.

Most of their scenarios are modeled after an 1895 earthquake with a magnitude of 6.4 that was centered in Charleston, Mo.

The preliminary results are sobering, said Rogers.

Data indicates ground shaking would be magnified about 600 percent within the flood plain of the Missouri River, a development that would cause most of Missouri’s existing long-span bridges to collapse.

"You don't even need a really big earthquake to do significant damage in Missouri," Rogers says. "It could happen tomorrow."

The relative quake risk of the New Madrid seismic zone is a great debate that might be driven in part by competition for grant money, Forte said.

Those scientists who work on West Coast quakes have an incentive to claim that the research money should be spent on that region, while the central continent-focused researchers obviously are more invested in funds coming their way.

Copyright © 2008 Imaginova Corp. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.

[lurkey]

Scientists say Midwest quakes poorly understood


Apr 19, 9:56 AM (ET)

By DAVID MERCER


CHAMPAIGN, Ill. (AP) - Scientists say they know far too little about Midwestern seismic zones like the one that rumbled to life under southern Illinois Friday morning, but some of what they do know is unnerving.

The fault zones beneath the Mississippi River Valley have produced some of the largest modern U.S. quakes east of the Rockies, a region covered with old buildings not built to withstand seismic activity.

And, when quakes happen, they're felt far and wide, their vibrations propagated over hundreds of miles of bedrock.

Friday's quake shook things up from Nebraska to Atlanta, rattling nerves but doing little damage and seriously hurting no one. It was a magnitude 5.2 temblor centered just outside West Salem in southeastern Illinois, a largely rural region of small towns that sit over the Wabash fault zone. The area has produced moderately strong quakes as recently as 2002.

But it hasn't been studied to nearly the degree of quake-prone areas west of the Rockies, particularly along the heavily scrutinized Pacific coast.

"We don't have as many opportunities as in California," said Genda Chen, associate professor of engineering at the University of Missouri-Rolla, which sits near the well-known and very active New Madrid fault zone.

"We cannot even borrow on the knowledge they learn on the West Coast" because quakes that happen in California - where tectonic plates beneath the Earth's surface collide - are so different from Midwestern quakes that happen far away from the edges of the nearest plates.

It isn't entirely clear, for instance, whether the Wabash faults are related to the New Madrid faults or not.

Some scientists say they are related, noting that the Wabash faults, which roughly parallel the river of the same name in southern Illinois and Indiana, are a northern extension of the New Madrid zone. Others say they're not.


The New Madrid fault zone produced a series of quakes in 1811 and 1812 that reached an estimated magnitude 7.0, putting them among the strongest known quakes to have occurred east of the Rockies. The quakes changed the course of the Mississippi River and were felt in New England.

That distance of well over a thousand miles sounds impressive, but experts say quakes that happen in the Midwest commonly radiate out for hundreds of miles because of the bedrock beneath much of the eastern United States.

"Our bedrock here is old, really rigid and sends those waves a long way," said Bob Bauer, a geologist with the Illinois State Geological Survey who works in Champaign.

He compared the underground rock, which in much of the Midwest lies anywhere from a few thousand feet to just a few feet below the earth's surface, to a bell that very efficiently transmits seismic waves like sound.

"California is young bedrock," he explained. "It's broken up ... like a cracked bell. You ring that, the waves don't go as far."

The question of whether Friday's quake was centered along a branch of the New Madrid zone or not is of more than academic interest. The area even now produces smaller, very regular quakes, and experts say it still has the potential to produce a quake that could devastate the region.

The Wabash faults have the potential to do the same, at least based on distant history, said Columbia University seismologist Won-Young Kim.

The strongest quake produced in recent history by the Wabash was a magnitude 5.3 in southern Illinois in 1968, but researchers have found evidence that 4,000 to 6,000 years ago, much stronger quakes shook the region, Kim said, as strong as magnitude 7.0 or more.

A similar quake is still possible, if the region is given time to build up enough energy, Kim said. But knowledge about the area is too thin to say whether that's likely, he added.

[HurricaneBill]

Major quake almost inevitable for California

California's last Magnitude 7 earthquake was the 7.1 earthquake that struck Hector Mine on October 16, 1999.

[somethingfunny]

Most of the other seismic zones around the Pacific Rim (Peru, Solomons, Kamchatka, northern Japan...) have seen some strong earthquakes within the past year or two. How does that translate stress to the other fault zones around the Pacific?

[Matt-hurricanewatcher]

If the faults are close or innerconnected, I would believe that it would relieve some of the stress making it less likely for a mega earthquake to develop on that fault. But each fault has its own stresses they are under, so its really hard to tell. Its like the sanandreas fault that runs through California, that is called a transform boundry. Meaning two faults are the North American and the Pacific slide by each other. Also to make my point clear this can have a 7.5-8.2 earthquake and not cause any stress or strain on the casecada subduction zone, that lays from southwestern Canada to Southern Oregon. This zone is a convergent boundry like the indian ocean fault that had the 9.2 earthquake. So the big subduction fault is still building up pressure, and so keep doing so intill it breaks. Another question is could another close earthquake cause another fault close to it to release? I believe it could.

[lurkey]

Quake shakes downtown Reno; no damage immediately apparent
Thu Apr 24, 7:27 PM ET


RENO, Nev. - An earthquake has shaken buildings in downtown Reno, but there are no immediate reports of damage.

The U.S. Geological Survey reports that a magnitude 4.1 quake hit just before 4 p.m. Thursday and was centered 4 miles west-northwest of Reno.

The survey says the quake followed smaller ones just beforehand. Several small quakes have been centered in the area in recent weeks.

Details

[lurkey]

Reno urged to prepare for worse as earthquakes continue
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Apr 26, 6:18 PM (ET)

By MARTIN GRIFFITH


RENO, Nev. (AP) - Scientists urged residents of northern Nevada's largest city to prepare for a bigger event as the area continued rumbling Saturday after the largest earthquake in a two-month-long series of temblors.

More than 100 aftershocks were recorded on the western edge of the city after a magnitude 4.7 quake hit Friday night, the strongest quake around Reno since one measuring 5.1 in 1953, said researchers at the seismological laboratory at the University of Nevada, Reno.

The latest quake swept store shelves clean, cracked walls in homes and dislodged rocks on hillsides, but there were no reports of injuries or widespread major damage.

Seismologists said the recent activity is unusual because the quakes started out small and continue to build in strength. The normal pattern is for a main quake followed by smaller aftershocks.

(AP) Keith Phillips checks the damage to his house in Mogul, Nev., Saturday morning April 26, 2006. ...
Full Image
"A magnitude 6 quake wouldn't be a scientific surprise," John Anderson, director of the seismological lab, said Saturday. "We certainly hope residents are taking the threat seriously after last night."

But Anderson stressed there was no way to predict what would happen, and said the sequence of quakes also could end without a major one.

Reno's last major quake measured 6.1 on April 24, 1914, and was felt as far away as Berkeley, Calif., said Craig dePolo, research geologist with the Nevada Bureau of Mines and Geology.

A rockslide triggered by Friday night's quake was blamed for causing a 125-foot breach in a wooden flume that carries water to one of two water treatment plants in Reno, a city of about 210,000.

A backup pump was used to divert water to the plant, and the breach was not expected to cause any water shortages, said Aaron Kenneston, Washoe County emergency management officer.

The U.S. Geological Survey said Friday night's quake was centered around Mogul, just west of Reno. The area of upscale homes along the eastern Sierra was rattled by more than 100 quakes the day before, the strongest a magnitude 4.2 that caused high-rise casinos to sway in downtown Reno.

The strongest aftershock measured 3.7 and was recorded after noon Saturday.

Mike Lentini of Reno said Friday night's quake felt "like a big truck hit the building" and awakened his family.

"It's the unknown. It's shaking, and when's it going to stop?" he said Saturday. "And when stuff starts falling off the shelves it's a whole other ballgame."

Jars of mayonnaise and bottles of ketchup and shampoo fell from shelves at a Wal-Mart store in northwest Reno. Overhead televisions swayed at a sports bar in neighboring Sparks, 11 miles east, where bartender Shawn Jones said the rumble was significantly stronger than Thursday's event.

"The bottles were shaking, so I sent everybody outside," he said.

Hundreds of mostly minor quakes have occurred along one or possibly more faults since the sequence began Feb. 28, said Ken Smith, a seismologist at the Reno laboratory. The quakes have occurred along an area about 2 miles long and a half-mile wide.

"We can't put a number on it, but the probability of a major earthquake has increased with this sequence," Smith said Saturday. "People need to prepare for ground shaking because there's no way to say how this will play out."

Among other things, scientists urged residents to stock up on water and food, to learn how to turn off water and gas, and to strap down bookshelves, televisions and computers.

"It's getting a little bit frightening," Daryl DiBitonto of Reno told the Reno Gazette-Journal. "I'm very concerned about this increase in not only activity, but also in magnitude."

The quakes around Reno began a week after a magnitude 6 temblor in the northern Nevada town of Wells, near the Utah border. The Feb. 21 quake caused an estimated $778,000 in damage to homes, schools and historic downtown buildings, dePolo said.

Scientists said they're unsure whether the seismic activity at opposite sides of Nevada is related.

Nevada is the third most seismically active state in the U.S. behind California and Alaska. The Wells quake was the 15th of at least magnitude 6 in the state's 143-year history.

A magnitude-7.4 quake south of Winnemucca in 1915 is the most powerful in state history.

---

Associated Press writer Scott Sonner in Reno contributed to this report.


Map/Details

[lurkey]

Earthquake rattles Mexico City


MEXICO CITY, Mexico (CNN) -- A moderate earthquake of 5.8 magnitude struck southwestern Mexico on Sunday night, according to the U.S. Geological Survey.

Rafael Abreau of the USGS said there were no reports of damage from the earthquake, which was centered about 54.5 miles (87.7 kilometers) below ground, and about 100 miles (161 kilometers) south-southwest of Mexico City.

Abreau said the USGS had received reports that the earthquake had been felt in the country's capital.

Because of the depth of the earthquake, Abreau said, "we may see some minor damage."

"Yes, it scared us," Julio Lara, 38, a parking attendant in downtown Mexico City told The Associated Press. "It was strong."

The earthquake struck at 7:06 p.m. local time (8:06 p.m. ET).

[CajunMama]

Look at all the reported earthquakes around reno for the last week

http://earthquake.usgs.gov/eqcenter/recenteqsus/Maps/US2/39.41.-121.-119_eqs.php

[lurkey]

Look at all the reported earthquakes around reno for the last week

http://earthquake.usgs.gov/eqcenter/recenteqsus/Maps/US2/39.41.-121.-119_eqs.php

someone on twitter from CA said thought they were being surrounded (Oregon from the north, Nevada from the east and Mexico from the south)and they were next . . .

[mrslinarcos]

I totally agree; I think this is definitely leading up to something much bigger. It would be wrong
to not assume that just because it's happening N. S. and E. that all is good for CA. Not in the
least.

[lurkey]

Moderate earthquake rocks northern California

(CNN) -- A magnitude 5.2 earthquake shook a rural part of northern California on Tuesday evening, according to the U.S. Geological Survey.

The moderate quake hit shortly after 8 p.m. (11 p.m. ET) about 11 miles east-southeast of Willow Creek, which is about 190 miles northwest of Sacramento.

Nita Rowley with the Williow Creek Chamber of Commerce said she felt the earthquake as a rolling jolt, but had not received any reports of damage.

At the Humboldt County Sheriff's Office in Eureka, Sgt. Diana Freese said several people had called to ask whether a quake had struck. She said the office had received no reports of injuries or damage.

"It was a roll and a shake," she said.

[HurricaneBill]

"It was a roll and a shake," she said.

A roll and a shake?

[masaji79]

Seems like earthquake activity is picking up across the entire U.S. The Illinois, Reno, Washington and California all have had substantial quakes in the last few weeks. Maybe we are looking at something big on the horizon.

[lurkey]

Seems like earthquake activity is picking up across the entire U.S. The Illinois, Reno, Washington and California all have had substantial quakes in the last few weeks. Maybe we are looking at something big on the horizon.

There were also a few rumblings in New York, a several months back. ..