A magnitude 4.0 earthquake struck off the coast of San Diego this morning. There were no immediate reports of damage or injuries.
The quake struck 7:34 a.m. about 30 miles west of La Jolla and 37 miles west of San Diego, according to the U.S. Geological Survey. The quake originated about 12 miles underground, the USGS estimated.
The shaker was felt across San Diego County including Oceanside, Escondido, Vista and Carlsbad, as well as in Temecula, Laguna Niguel and Ladera Ranch.
Under the central part of the San Andreas fault, the deep seismic whisperings known as tremors have increased after two recent large earthquakes, and a surge in tremors appears to have foreshadowed one of them, according to a study to be published Friday in the journal Science.
“It reaffirms the need to be ready,” said Robert Nadeau, a research seismologist at UC Berkeley who led the study. “The San Andreas fault is changing down deep and it’s changing down deep in places where large earthquakes have happened in the past.”
Among the findings was an unusually strong tremor episode three weeks before the magnitude-6.0 Parkfield earthquake in 2004. If more of these kinds of signals are found before other large earthquakes, they could provide a kind of early warning, said Greg Beroza, a seismologist at Stanford University who was not involved in this study.
“There have been plenty of tremor episodes that have not triggered earthquakes in other places,” he said. “This one might make the strongest case.”
Predicting large quakes with precision is the elusive Holy Grail. Scientists have only been able to calculate probabilities for quakes in certain areas by analyzing a time line of ruptures and calculating the amount of stress building on a fault. The latest study may potentially inch us closer to having an actual predictor, scientists said.
Earthquakes typically generate clear seismic waves with sharp onsets, tailing off after a minute or two, seismologists said. Tremors vibrate quietly and can continue for days. Tremors also tend to happen in a deeper, softer part of the Earth’s crust than the upper part typically thought to generate earthquakes.
Seismologists used to ignore tremors because they looked like noise in the data caused by wind or cars.
Until recently, scientists also had difficulty storing the enormous amounts of data required to detect tremors. About 10 years ago, Japanese seismologists discovered deep tremors when they took a closer look at the background noise.
Since then, scientists have detected tremors in the Pacific Northwest and below the San Andreas. Nadeau’s study focused on the San Andreas fault in the Parkfield region, about 170 miles northwest of Los Angeles.
Nadeau and graduate student Aurelie Guilhem combed through seismometer data from July 2001 to February 2009. That period included two strong earthquakes: the magnitude-6.5 San Simeon earthquake of 2003 and the Parkfield temblor the next year. Even though the San Simeon quake originated on a fault about 40 miles away from the San Andreas fault in Parkfield, the quake appeared to set off stress changes under the San Andreas, Nadeau said.
The tremor activity in the Parkfield area 45 days after the San Simeon quake more than doubled compared with the 45 days before the quake. About eight months later, they saw a five-day spike of tremors about 10 times more active than the average before the San Simeon quake. The tremors quieted, but the Parkfield earthquake hit about three weeks later on the San Andreas.
This surge can be considered a “foretremor” of the Parkfield quake because the events are close together in time, Nadeau said. But, he added, “we don’t have enough resolution to say there’s a mechanical connection between the two.”
The Parkfield quake appeared to stimulate the tremors again, raising the activity level to about six times the level before the San Simeon quake. Since then, tremor activity has remained high, varying from 1.5 to two times the level before the San Simeon quake.
Scientists still do not understand the exact relationship between tremors and quakes, Nadeau said. But more tremors probably means more stress on the fault, he said, and that suggests “an increased probability of an earthquake coming sooner rather than later.”
A new radar imaging system on the belly of a Gulfstream jet that is flying over California’s complicated network of faults has started collecting some of the most detailed images yet of the Earth’s surface shifting and straining with seismic energy, scientists at NASA’s Jet Propulsion Laboratory said.
“This will show us where the faults are active,” said Andrea Donnellan, a JPL geophysicist who is one of the project’s principal investigators. “Where the ground is moving tells us what’s going on at depth.”
The data from this project could help scientists figure out where the risk of earthquake activity is highest, though the data will never be so specific as to predict a day, location and magnitude of a quake, she said. “This will help us with the five- to 10-year time horizons,” Donnellan said. “We can see hot spot maps and ... figure out where to target our retrofitting.”
The device, the Uninhabited Aerial Vehicle Synthetic Aperture Radar (even though it is currently being used on a human-piloted plane), mounted on the plane shoots long-wavelength radar beams at features on the ground and measures the reflections.
Based at NASA’s Dryden Flight Research Center at Edwards Air Force Base, the plane flies about 45,000 feet above the ground along GPS-guided trajectories.
The project will map faults across about 70% of California, including a wide swath of Southern California, said the project’s chief scientist, Scott Hensley.
Two small earthquakes separated by 47 seconds shook an area a few miles west of the Malibu coast Saturday night, according to the U.S. Geological Survey.
The first quake, which registered a magnitude of 2.8, hit about six miles northwest of Malibu at 8:39 p.m. The second one, which was close to the first and registered 2.6, struck at 8:40 p.m.
The quakes were centered about 35 to 38 miles west of downtown Los Angeles. There were no immediate reports of damage or injuries.
A 3.3 earthquake rattled parts of the Inland Empire this morning, but there were no reports of damage of injuries.
The temblor struck around 7:30 a.m. Sunday in San Bernardino, about 50 miles east of Los Angeles. According to the U.S. Geological Survey, the quake hit about 10 miles underground.
Residents in San Bernardino, RIalto, Fontana and surrounding communities reported feeling the jolt.
A moderate earthquake jolted a remote area of Central California today, according to the National Earthquake Information Center of the U.S. Geological Survey.
It struck at roughly 3:50 p.m. about seven miles southeast of the small town of Keelerin unincorporated Inyo County, and registered a 4.7 magnitude, said Dale Grant, a Colorado-based geophysicist for the agency.
"There were no reports of damage or injury, but there were reports of it being felt," Grant said.
The union representing Los Angeles police officers is pressuring the owner of San Diego’s main newspaper to change the paper’s editorial stance on labor issues or to fire its editorial writers.
The feud is rooted in the recent purchase of the San Diego Union-Tribune by Platinum Equity, a private Beverly Hills firm.
Platinum relies on a $30-million investment from the pension fund of Los Angeles police officers and fire fighters, along with large sums from other public-employee pension systems around the state, to help fund its acquisitions of companies. As League President Paul M. Weber views it, that makes the League part owner in the flagging Tribune and League officials are none to happy with the paper’s consistent position that San Diego lawmakers should cut back on salaries and benefits for public employees in order to help close gaping budget deficits.
"Since the very public employees they continually criticize are now their owners, we strongly believe that those who currently run the editorial pages should be replaced," Weber wrote in a March 26 letter to Platinum CEO Tom Gores.
Weber, in an interview, emphasized that the League is not demanding changes in the paper’s news coverage of the issue or in its staff of reporters. "It’s just these people on the opinion side. There is not even an attempt to be even-handed. They’re one step away from saying, ‘these public employees are parasites,’ " Weber said.
Bob Kittle, editor of the Union-Tribune’s editorial page, rebuffed Weber’s comments. While his staff has written several editorials critical of the benefit and pension commitments city leaders have made to San Diego’s five public employee unions, he denied Weber’s charge that the paper is out to hurt public employees.
Apartment tenants displaced by Tuesday’s magnitude 4.0 aftershock are expected to return to their Long Beach apartment building Thursday.
The 12 tenants of 2283 Locust Ave. expect to spend one more night at California Recreation Center Park, about two miles from their homes. The families were required to vacate their apartments, which suffered superficial damage from an aftershock two days after a 4.7 magnitude quake rattled Los Angeles County.
“From what I heard, plaster was starting to come off their walls, and that needed to be taken care of before the people returned,” said Guillermo Sanchez, a spokesman for the American Red Cross.
Sanchez said the landlord was unable to complete the repairs today as originally planned.
Authorities ordered a Long Beach apartment building evacuated after the structure sustained severe roof damage in a quake that rattled the area earlier in the day.
At least six families were ordered to evacuate their apartments and were awaiting placement in temporary housing by the Red Cross, according to the Long Beach Fire Department. Nobody was injured during the 4.0 magnitude quake, although a chunk of the building's eaves gave way and fell to the ground.
The aftershock occurred near the epicenter of Sunday’s 4.7 quake, which caused strong shaking and light damage in the beach towns south of the airport.
Although a few fire stations in the Rancho Palos Verdes and Carson areas reported items falling off their shelves, the Los Angeles County Fire Department did not receive any reports of significant damage, said Inspector Frank Garrido.
A magnitude 4.0 earthquake shook the Hawthorne and Lennox area this afternoon, an aftershock of Sunday’s 4.7 temblor, Caltech officials said.
The earthquake occurred about 3:50 p.m. from a rupture about 7.5 miles underground, said seismologist Egill Hauksson. Preliminary data showed that it was less than a mile southeast of Sunday’s quake, he said.
Although a few fire stations in the Rancho Palos Verdes and Carson areas reported items falling off their shelves, the Los Angeles County Fire Department did not receive any reports of significant damage, said Inspector Frank Garrido.
Hauksson said there have been about a dozen aftershocks since Sunday’s quake.
Tuesday’s quake had its own magnitude 2.5 aftershock, which followed about two minutes later, Hauksson said.
The seismologist said all of the quakes are believed to have originated from the Newport-Inglewood fault zone, the source of the 1933 Long Beach earthquake.
Updated at 6 p.m.: The earthquake has been downgraded to a magnitude 4.0.
A magnitude 4.1 earthquake struck this afternoon about two miles north of Hawthorne, close to the epicenter of Sunday's 4.7 temblor.
It's unclear whether the quake was an aftershock of the Sunday quake, which caused minor damage in the South Bay.
The quake erupted about 7.5 miles below the surface, according to the U.S. Geological Survey.
Updated at 4:20 p.m.:There were no immediate reports of damage or injuries, but the quake rattled nerves of some South Bay residents who felt it strongest. The Los Angeles Fire Department went on alert, but spokesman Brian Humphrey said via Twitter that the department found no evidence of injuries or fires.
The epicenters of both quakes are located east of Los Angeles International Airport and south of Hollywood Park. The epicenter of this afternoon’s earthquake is about 3,500 feet southeast of Sunday’s. The epicenter was at West 112th Street and South Lemoli Avenue near West Imperial Highway and Crenshaw Boulevard.
Officials at Caltech said today's quake was an aftershock of Sunday's quake.
--Andrew Blankstein, Rong-Gong Lin II and Jia-Rui Chong
Seismologists suspect that the magnitude-4.7 earthquake that shook a large stretch of Southern California on Sunday night erupted along the Newport-Inglewood fault, which experts have long feared would produce a devastating temblor.
"The initial focal mechanism is consistent with a slip on the Newport-Inglewood fault, which was the source of the damaging 1933 Long Beach earthquake," the U.S. Geological Survey said in a statement. "Two of the early aftershocks, however, are west of the Newport-Inglewood fault trend. Later aftershocks will help to define the fault plane that ruptured."
USGS officials are not sure whether Sunday's temblor occurred on the Newport-Inglewood but noted that a 1920 quake in the same area erupted on that fault line.
The quake hit at 8:39 p.m. and was centered near Lennox, a community between Inglewood and Hawthorne and east of Los Angeles International Airport. Lasting about 15 seconds, the temblor could be felt as far away as the high desert, Indio, Carpinteria and San Diego County. There were no reports of major damage or injuries.
The earthquake was "a bit deep," originating 8.4 miles below the surface, said U.S. Geological Survey seismologist Susan Hough. "That tends to make it less sharp -- less of a jerky, abrupt motion."
As a result, most of the region felt the quake as a rolling motion, though some closer to the center may have felt a jolt.
The Newport-Inglewood fault, beginning just off the Orange County coast and extending 50 miles northwest through Long Beach, Inglewood and into West Los Angeles, is believed capable of generating a quake in the magnitude-7 range and has been the subject of dire quake scenarios because it runs directly under some of the most densely populated areas of Southern California.
Movement along the southern part of that fault caused the 1933 Long Beach quake, a 6.3 temblor centered off Newport Beach that killed 115 people, mainly in Long Beach and Compton. That was the second-largest number of fatalities in a California temblor in recorded history. Damage to school buildings caused by that quake led to major steps toward earthquake-resistant construction in the state.
A study by the Division of Mines and Geology found that a quake along the Newport-Inglewood fault could cause blockage of the Hollywood Freeway at the over-crossings for Hollywood and Sunset boulevards, reduction of the capacity of Los Angeles International Airport to 30% for two days, the indefinite loss of 34% of all hospital beds in Los Angeles and Orange counties, the shutdown of five power plants for three days and impediments in water supplies.
The USGS said in its statement that the Newport-Inglewood fault "was formerly thought to be capable of very large earthquakes. More recent research has shown that, instead, it is of less concern and only capable of up to about [magnitude] 7.4."
Though there was little damage, Sunday's temblor was felt across a wide area.
"It felt like all the windows were about to pop," said Joseph Poindexter, 36, of Los Angeles, who was inside the Hollywood Park Casino. "It sounded like a big sonic boom. Everybody started running or ducking under the tables."
Automatic sensors initially logged a magnitude 5, but as more data came in, seismologists downgraded it to a magnitude 4.7. A brief aftershock, registering 3.1, followed the quake at 8:45 p.m., also centered in the Lennox area.
At the Los Angeles County Sheriff's Department's Lennox station, deputies said the shaking was brief but intense.
"It was pretty strong but over in about 10 seconds," said Lt. Kent Wegener. "There are no [immediate] reports of damage. At this point, we are checking all the critical facilities and getting our ducks in a row."
Los Angeles city and county fire officials also said they had not received significant damage reports in residential or industrial areas, including the coastal refineries.
In Hawthorne, firefighters were called after a lightpole on Chadron Avenue, near Crenshaw Boulevard, was damaged during the earthquake. One man suffered a heart attack, but it was unclear whether that was connected to the quake.
"Luckily, nothing major so far," said Hawthorne Police Lt. Michael Ishii.
At the South Bay Galleria, south of the epicenter, ceiling tiles fell inside a movie theater. There were no injuries reported, though police were called to the scene to help reunite customers with belongings they'd left inside when rushing for the exits, said Redondo Beach Police Sgt. Scott Weibel.
--Scott Gold, Jean Merl, Jia-Rui Chong, Andrew Blankstein and Rong-Gong Lin II
Caption: No major damage was reported from the magnitude 4.7 earthquake centered in Lennox, but some windows broke near the epicenter. Credit: Lawrence K. Ho / Los Angeles Times
A 4.7 earthquake struck southeast of Los Angeles International Airport this evening, causing significant shaking across Southern California.
The temblor hit about 8:40 p.m. 3 miles from the South Bay community of Lennox. A 3.1 aftershock occurred a few minutes later.
The temblor started about 8.4 miles below the surface, according to the U.S. Geological Survey. Residents in the Lennox area said dishes fell off shelves, but there were no reports of serious damage.
It's unclear what fault the quake struck on. The Newport-Inglewood fault, which has produced several powerful temblors, runs through that general area.
An initial assessment by the Los Angeles Fire Department found "no major structural damage, no serious injuries," according to spokesman Brian Humphrey's Twitter feed.
At the Los Angeles County Sheriff's Department's Lennox station, deputies said the shaking was brief but intense. "It was pretty strong but over in about 10 seconds," said Lt. Kent Wegener. "There are no [immediate] reports of damage. At this point, we are checking all the critical facilities and getting our ducks in a row."
Los Angeles County fire officials also said they had not received damage reports in residential or industrial areas, including the coastal refineries.
KCAL-TV Channel 9 interviewed moviegoers at a shopping mall in Redondo Beach who said the quake shook the screen and caused some ceiling tiles to fall. But firefighters said there was no serious damage or injuries. KCAL also reported numerous burglar alarms going off and some people being cut by broken glass.
In Hawthorne, firefighters were called to Chadron Avenue, near Crenshaw Boulevard, where a light pole was damaged during the earthquake. One man also suffered a heart attack, but it was unclear whether that was connected to the quake. “Luckily, nothing major so far,” said Hawthorne Police Lt. Michael Ishii.
Some residents said they were having trouble with cellphone service, but it's unclear how widespread the problems are.
The earthquake was “a bit deep,” said U.S. Geological Survey seismologist Susan Hough – originating 8.4 miles below the surface. “That tends to make it less sharp – less of a jerky, abrupt motion,” Hough said. As a result, most of the region felt the quake as a rolling motion, though some closer to the center may have felt a jolt.
Lucy Jones, seismologist at the U.S. Geological Survey, said the earthquake appears to be consistent with a rupture on the Newport-Inglewood fault. She said the quake was too small to break the surface, so they can't definitively identify faults. Jones said this fault isn't typically thought to be capable of producing a large quake, like the San Andreas fault is known to do. But it was responsible for the 1933 Long Beach earthquake, which measured about 6.3 in magnitude. The Long Beach quake is about as big as seismologists expect from this fault, she said.
"There have been numerous magnitude 3s on it over the years, a cluster of them in the 1980s," she said. "In general, it's an active area."
The quake was initially logged as a magnitude 5 by automatic sensors, but as more data came in, seismologists downgraded it to a magnitude 4.7. It also had an aftershock with a magnitude of 3.1 about six minutes later. So far, Jones said, 12,000 people have reported feeling the shaking, including some in San Diego. She was not surprised at the number of people reporting, as the quake shook a densely inhabited area.
Nothing about the quake or its aftershocks looked unusual, she said. "It’s a real garden-variety California earthquake so far."
What’s notable about it is location with respect to people.
She said the most similar earthquake to this one was a temblor that shook the Inglewood area in 1920. That was classified as a "minor damaging shock."
Updated at 10:30 p.m.: "County fire dispatchers reported no damage at area refineries although units had responded to numerous alarms triggered by the quake," said Los Angeles County Fire Inspector Frank Garrado. "We have had some alarm activations but the [fire units] have reported false alarms [there]."
Disneyland temporarily closed rides when the quake occurred, but no problems were reported.
Updated at 11:05 p.m.: Plate-glass windows shattered at two businesses on South Street in Long Beach. The Daily Breeze posted photos showing bottles of wine and other grocery items scattered on the floor of an Albertson's store in Redondo Beach.
Updated at 11:35 p.m.: According to City News Service, the Chevron refinery in El Segundo had a "burnoff,'' in which excess refinery gases were burned. Police said burnoffs are standard procedure after an earthquake.
-- Shelby Grad, Scott Gold, Andrew Blankstein, Jean Merl and Rong-Gong Lin II
Photos: Employees of a Starbucks at Hawthorne and Artesia Boulevards in Torrance clean up glass that fell from a window above, reportedly injuring one person who was taken to a nearby hospital. Credit: Jay L. Clendenin / Los Angeles Times
An earthquake with an estimated magnitude of 4.7 occurred about 8:40 p.m. tonight two miles northeast of Hawthorne, according to the U.S. Geological Survey. Two aftershocks have been reported as of 9 p.m., the first, a 2.5 aftershock at 8:44 p.m. near El Segundo and the second at 8:45 p.m. northeast of Hawthorne, with an estimated magnitude of 3.1.
[Geologists initially estimated the magnitude of the quake as 5.0]
Click on the map icons above to read updates from specific locations.
A 5.0 earthquake struck southeast of Los Angeles International Airport this evening, causing significant shaking across Southern California. [Update: Quake was downgraded to 4.7.]
The temblor hit about 8:30 p.m. a mile from the South Bay community of Lennox.
There were no immediate reports of damage or injuries, but authorities said they were receiving numerous calls about the temblor.
A 3.0 aftershock occurred a few minutes later near Lennox.
Update at 8:58 p.m.: The temblor started about 8.4 miles below the surface, according to the U.S. Geological Survey. Residents in the Lennox area said china fell off shelves, but there were no reports of more serious damage. The Los Angeles Fire Department is on "emergency quake mode" as a precaution.
It's unclear what fault the quake struck on. The Newport-Inglewood fault, which has produced several powerful temblors, runs through that general area.
Updated at 9:10 p.m.: An initial assessment by the Los Angeles Fire Department found "no major structural damage, no serious injuries," according to spokesman Brian Humphrey's Twitter feed.
Updated at 9:20 p.m.: At the Los Angeles County Sheriff's Lennox station, deputies said the shaking was brief but intense. "It was pretty strong but over in about 10 seconds," said Lt. Kent Wegener. "There are no [immediate] reports of damage. At this point, we are checking all the critical facilities and getting our ducks in a row."
Los Angeles County Fire officials also said they had not received damage reports in residential or industrial areas, including the coastal refineries.
Update at 9:35 p.m.:KCAL interviewed moviegoers at a shopping mall in Redondo Beach who said the quake shook the screen and caused some ceiling tiles to fall. But firefighters said there was no serious damage or injuries. KCAL also reported numerous burglar alarms going off and some people cutting themselves on glass.
Updated at 9:50 p.m.: In Hawthorne, firefighters were called to Chadron Avenue, near Crenshaw Boulevard, where a light pole was damaged during the earthquake. One man also suffered a heart attack, but it was unclear whether that was connected. “Luckily, nothing major so far,” said Hawthorne Police Lt. Michael Ishii.
The earthquake was “a bit deep,” said U.S. Geological Survey seismologist Susan Hough – originating 8.4 miles below the surface. “That tends to make it less sharp – less of a jerky, abrupt motion,” Hough said. As a result, most of the region felt the quake largely as a rolling motion, though some closer to the center felt more of a jolt.
Lucy Jones, seismologist at the U.S. Geological Survey, said the earthquake appears to be consistent with a rupture on the Newport-Inglewood fault. (She said the quake was too small to break the surface, so they can't definitively identify faults.) Jones said this fault isn't typically thought to be capable of producing a major quake like the San Andreas fault. But it was responsible for the 1933 Long Beach earthquake, which measured about 6.3 in magnitude. The Long Beach quake was about as big as seismologists expect from this fault, she said.
"There have been numerous magnitude 3s on it over the years, a cluster of them in the 1980s," she said. "In general, it's an active area."
The quake was initially logged as a magnitude 5 by automatic sensors, but as more data came in, seismologists downgraded it to a magnitude 4.7. It also had an aftershock with a magnitude 3.1 about six minutes later. So far, Jones said, 12,000 people have reported feeling the shaking, including some people in San Diego. She was not surprised at the number of people reporting because the quake shook a pretty densely populated area.
Nothing about the quake or its aftershocks looked unusual, she said. "It’s a real garden variety California earthquake so far."
What’s notable about it is location with respect to people.
She said the most similar earthquake to this one was a temblor that shook the Inglewood area in 1920, and that one was classified as a "minor damaging shock."
--Shelby Grad, Scott Gold, Jia-Rui Chong and Andrew Blankstein
Photo: Employees of a Starbucks at Hawthorne and Artesia Boulevards clean up broken glass that shattered on the floor and
reportedly injured one person who was taken to a nearby hospital. (Jay Clendenin / Los Angeles Times)
A 4.2 earthquake struck near Ojai in Ventura County today, but there were no reports of injuries or damage.
The temblor struck four miles east of Ojai at 1:27 p.m. (that's about 60 miles northeast of downtown Los Angeles). It was felt in parts of Ventura County and surrounding areas.
It's one of several temblors to hit the region in recent weeks, including one near Westlake Village and several in the Yorba Linda area.
A magnitude 4.4 earthquake struck the Westlake Village area at 6:11 p.m., shaking a large swath of the region. There were no immediate reports of injuries.
The quake — centered in a hillside area seven miles from both Malibu and Westlake Village — could be felt in the San Fernando Valley and Ventura County.
One Westlake Village resident said the quake caused a strong jolt but that nothing fell off shelves.
[Updated at 7 p.m.: The Los Angeles Fire Department reported that an elderly woman was injured when she fled her apartment during the quake and fell down.]
A mother who had claimed that an attacker knocked her out and abducted her 18-month-old daughter was arrested for allegedly killing the child.
Los Angeles County sheriff’s spokesman Steve Whitmore said Stacey Barker, 24, was arrested Thursday afternoon at her parents' home in Lancaster and is being held in lieu of $1-million bail. A day after her daughter’s March 18 disappearance, Barker recanted the tale of assault and abduction that launched a massive hunt. She then helped sheriff’s detectives find Emma Leigh’s body and told them the girl died in an accident.
Barker had initially told detectives that she was at a Lancaster park last month near the 14 Freeway and had just placed Emma in her car seat when she was "struck from behind by an unknown assailant."
Barker insisted that she awoke about 10:30 p.m., five hours later and several miles away at a Palmdale park-and-ride on Avenue S, and that her daughter was missing. After Barker recanted, detectives discovered the toddlerby the side of a road in Sylmar, near the 5 Freeway.
The body, found near Roxford Street and El Dorado Avenue, was concealed by deep overgrown brush alongside a fence. Authorities said it appeared that the body, which showed no visible signs of trauma, had been dumped within the previous 24 hours. Coroner’s officials in recent weeks conducted an autopsy and other tests to determine the cause of death.
There has been much debate about an Italian scientist's prediction of a quake in Italy several days before one occurred near Rome. The scientist said changes in gas levels from the earth's crust suggest a quake was coming -- a method that other experts say has been discredited.
Among the scientists voicing some skepticism about Giampaolo Giuliani’s claims was Vladimir Keilis-Borok, a professor in residence at UCLA’s Department of Earth and Space Sciences.
“Certainly such announcements should be accompanied by the track record,” Keilis-Borok said. “You have to tell how you monitored radon for so many years and say, ‘I made so many correct predictions and so many false alarms.’ Without this information I cannot judge how he did.”
Indeed, this is the way earthquake scientists have judged Keilis-Borok, who became a sensation when he predicted -- in a general way -- a quake off the coast of Hokkaido, Japan, and the San Simeon earthquake in 2003.
The UCLA professor lost some of his star power when an earthquake predicted for the Southern California desert by September 2004 failed to materialize. “I made for California two predictions,” he said. “One was correct and the second was wrong.
"Each time we indicated the probability of false alarm was 50% so I would say that experiment was successful,” he said. He hasn’t given up on his approach, which looks at “precursory chains” of small quakes that had occurred in the past to develop predictions about larger quakes that would occur in the future. He said that his method had predicted 10 out of 14 earthquakes of magnitude 8 or greater worldwide.
Collaborators in Italy have made a few recent predictions in their country, Keilis-Borok said. But he acknowledged that, as far as predicting Monday's temblor, one was a “failure to predict” and the other was a “near miss.”
“Prediction is going to have limited accuracy,” he said. “It’s like military intelligence. Any meaningful improvement of knowledge is important.”
The U.S. Geological Survey reported that a magnitude 2.5 earthquake struck one mile northwest of downtown Los Angeles at 10:07 p.m. Tuesday, at a depth of roughly 6 miles.
A little over a week ago, a scientist little known in earthquake circles made a bold prediction of a destructive earthquake around the small town of Sulmona, Italy, based on readings of radon gas. Giampaolo Giuliani went so far as to tell the mayor of Sulmona that it would strike within the next 24 hours. The deadline passed, and nothing happened.
Then, early Tuesday, a magnitude 6.3 earthquake struck about 35 miles away, near the town of L’aquila, sparking a controversy in Italy and around the world about whether Guiliani actually predicted the temblor. That prediction is the latest twist in the maddening scientific quest to predict earthquakes.
The history of earthquake prediction is littered with a lot of discarded ideas, including, many scientists say, the radon theory. Guiliani said he was collecting samples of radon gases escaping from the earth’s crust in the area around the quake. He detected unusual readings and concluded that a big quake was imminent.
Using radon gas to predict quakes was popular in California in the late 1970s. Researchers at USC, Cal Tech and elsewhere believed changes in the gas levels were a precursor of quakes. In 1979, researchers found gas irregularities before two significant quakes, in Malibu and Big Bear. But the radon method began to lose steam because it could not reliably predict quakes.
Susan Hough, scientist in charge at the U.S. Geological Survey in Pasadena, who is finishing a book on earthquake prediction, said she hadn’t heard of Guiliani, but she wasn’t surprised that someone was claiming to have predicted the L’aquila quake.
“If you want predictions, they’re out there all the time,” Hough said. “It amazes me all the time that earthquakes happen that aren’t predicted because scientists and amateurs, everybody’s playing the game.”
The magnitude-3.3 earthquake occurred around 1:13 a.m. and the 3.0 around 7:11 a.m. about 10 miles southeast of town, according to a monitoring system run by the U.S. Geological Survey and UC Berkeley. For the last week, more than 15 other earthquakes have shaken the area, ranging in magnitude from 0.2 to 1.9.
"It's not a big deal," said Caltech seismologist Kate Hutton. "That's another swarm area."
A small earthquake struck the Chino Hills area today, the latest in a series of minor tremors that have hit the hilly suburban community this weekend.
Today’s 1.5-magnitude quake struck at 6:32 a.m. two miles west of the city and 8.3 miles below the surface, according to the United States Geological Survey. It was at least the seventh small quake in the area since Friday. The largest was a 1.9-magnitude temblor on Friday night, followed by a 1.8 jolt Saturday and others leading to today’s activity, according to a USGS website.
The quakes caused no apparent damage.
Last July, a 5.4-magnitude quake struck below Chino Hills and was felt as far away as Las Vegas. Only minor injuries were reported in that shake, including five people at a Wilshire district building in Los Angeles.
The series of Chino Hills quakes comes amid a swarm of small-to-moderate earthquakes that have hit the remote desert area around the Salton Sea southeast of Indio. Hundreds of shakers were recorded over the last eight days; the largest was a 4.8 jolt Tuesday.
Some scientists worry about quakes in that area, including swarms of tremors that come in waves roughly every couple of years around the Salton Sea. The scientists say a strong earthquake that begins at the sea’s Bombay Beach community and moves northwest along the San Andreas fault could be devastating for Los Angeles.
Earthquakes continued to rattle the Salton Sea area as a magnitude 4.0 quake rumbled through Wednesday at around 8:25 p.m.
More than 260 temblors have swarmed the area since Saturday, ranging from 0.4 to 4.8 in magnitude, said Caltech seismologist Kate Hutton. At least 12 of the quakes have measured 3.0 or above.
"We don't expect it to stop suddenly," Hutton said. "Most swarms go on for a week."
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