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Los Angeles warned to brace itself for a 'big one': Nasa says there is a 99.9% chance of a 5.0 earthquake in the next three years

Nasa is basing prediction on a study of the 2014 La Habra earthquake
This relieved stress in fault system and shifted upper sediments in LA
Deeper portions of these faults remain locked and map produce quakes
US Geological Survey (USGS) has said Nasa's analysis is wrong, and there's only 85 per cent chance this could happen

By Ellie Zolfagharifard For Dailymail.com

Published: 16:56 EST, 21 October 2015 | Updated: 09:04 EST, 22 October 2015

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Los Angeles residents should brace themselves for a big earthquake, Nasa has warned.

The space agency says it is 99.9 per cent sure that LA will be hit by a 5.0 magnitude earthquake in the next three years.

It's basing its prediction on a study of the La Habra earthquake that shook Greater Los Angeles last year.

But in a rare public disagreement, the US Geological Survey (USGS) has said Nasa's analysis is wrong, and there's only 85 per cent chance this could happen.

Pictured is Setting of the La Habra quake. Red dots show the magnitude 5.1 main shock, magnitude 4.1 aftershock and magnitude 5.4 Chino quake in 2008. Relocated aftershocks are green dots. Modeled faults are in brown, with the heavier reddish brown line denoting the bottom of the fault and labeled with italics

In Nasa's study, a team led by geophysicist Andrea Donnellan used GPS and airborne radar data to measure surface changes in Earth's crust caused by the March 28, 2014, earthquake.

Their study found the quake deformed Earth's crust across the northern Los Angeles Basin and northern Orange County.

Donnellan explained that when the earthquake struck it relieved some of the stress in the fault system and shifted some of the upper sediments in the LA basin.

The earthquake was felt widely in Orange, Los Angeles, Ventura, Riverside, San Bernardino, Kern and San Diego counties.

Radar observations spanning the La Habra quake. Top left shows northward-looking lines covering La Habra to the south and the San Gabriel Valley to the north. Top right shows southward-looking lines covering La Habra and the San Gabriel Valley

While the earthquake was relatively moderate in size, the earthquake's depth, at 3.6 miles (5.85km), combined with its location caused more than $12 million in damage.

RISK OF MAGNITUDE 8 EARTHQUAKE HAS INCREASED, WARNS STUDY

A new report in April from the U.S. Geological Survey warned the risk of 'the big one' hitting California has increased dramatically.

Researchers analysed the latest data from the state's complex system of active geological faults, as well as new methods for translating these data into earthquake likelihoods.

The estimate for the likelihood that California will experience a magnitude 8 or larger earthquake in the next 30 years has increased from about 4.7 per cent to about 7.0 per cent, they say.

'We are fortunate that seismic activity in California has been relatively low over the past century,' said Tom Jordan, Director of the Southern California Earthquake Center and a co-author of the study.

'But we know that tectonic forces are continually tightening the springs of the San Andreas fault system, making big quakes inevitable.

Most of the damage occurred within a 3.7-mile (6km) radius of the epicentre of La Habra, with a substantial amount of damage south of the main rupture.

The team's results show that even moderate earthquakes near Los Angeles can produce ground deformation and damage to water mains away from their epicenters.

Using computer models, scientists found that the best explanation for the observed ground deformation was shallow movement along several active buried fault-like zone.

These included; the West Coyote Hills in northern Orange County; in the Chino Hills on the border of Orange, Los Angeles and San Bernardino Counties; and in the San Gabriel Valley.

It is likely the deeper portions of these faults remain locked and are capable of producing future earthquakes.

'The earthquake faults in this region are part of a system of faults,' said Donnellan.

'They can move together in an earthquake and produce measurable surface deformation, even during moderate magnitude earthquakes.

'This fault system accommodates the ongoing shortening of Earth's crust in the northern Los Angeles region.'

Donnellan said a future earthquake to release the accumulated strain on these faults could occur on any one or several of these structures, which may not have been mapped at the surface.

Los Angeles residents should brace themselves for a big earthquake, Nasa has warned. The space agency says it is 99.9 per cent sure that LA will be hit by a 5.0 magnitude earthquake in the next three years. While it work be as big as the earthquake in the film San Andreas, it could still cause significant damage

But the US Geological survey is in disagreement with Nasa's results.

'The area — a 100 km radius circle centered on the city of La Habra — is a known seismically active area,' they said in a statement.

'For this same area, the community developed and accepted model of earthquake occurrence, 'UCERF3,' which is the basis of the USGS National Seismic Hazard Maps, gives a three-year probability of 85 per cent.

'In other words, the accepted random chance of an M5 or greater in this area in three years is 85 per cent, independent of the analysis in this paper.'

The disaster film, 'San Andreas', has put California's tremors in the spotlight over the past year.

The U.S. Geological Survey has, however, previously warned the risk of 'the big one' hitting California has increased dramatically.

The disaster film, 'San Andreas', has put California's tremors in the spotlight over the past year. The U.S. Geological Survey has, however, previously warned the risk of 'the big one' hitting California has increased

Researchers analysed the latest data from the state's complex system of active geological faults, as well as new methods for translating these data into earthquake likelihoods.

The estimate for the likelihood that California will experience a magnitude 8 or larger earthquake in the next 30 years has increased from about 4.7 per cent to about 7.0 per cent, they say.

'But we know that tectonic forces are continually tightening the springs of the San Andreas fault system, making big quakes inevitable.

La Habra is a city located in the northwestern corner of Orange County, California

IT'S NOT JUST SAN ANDREAS: SCIENTISTS REVEAL MORE HIDDEN HAZARDS

The new disaster film, 'San Andreas', has put the major Californian fault in the spotlight.

But a study in May found it isn't just the San Andreas fault we should be worried about; a very real threat of earthquakes and tsunamis lurks offshore Southern California.

Researchers say that several long faults could cause magnitude 8.0 quakes and tsunamis within 90 miles (145km) of the coast.

'We're dealing with continental collision,' said geologist Mark Legg of Legg Geophysical in Huntington Beach, California, regarding the cause of the offshore danger.

'That's fundamental. That's why we have this mess of a complicated logjam.'

The logjam Legg referred to is composed of blocks of the Earth's crust caught in the ongoing tectonic battle between the North American tectonic plate and the Pacific plate.

This map shows the California Borderland and its major tectonic features, as well as the locations of earthquakes greater than magnitude 5.5. The dashed box shows the area of the new study. Large arrows show relative plate motion for the Pacific-North America fault boundary

The blocks are wedged together all the way from the San Andreas Fault on the east, to the edge of the continental shelf on the west, from 90 to 125 miles (150 to 200km) offshore.

These chunks of crust get squeezed and rotated as the Pacific plate slides northwest, away from California, relative to the North American plate.

The mostly underwater part of this region is called the California Continental Borderland, and includes the Channel Islands.

Researchers combined older seafloor data and digital seismic data from earthquakes along with 2,796 miles (4,500km) of new seafloor depth measurements collected in 2010.

What they found along the Santa Cruz-Catalina Ridge Fault are ridges, valleys and other clear signs that the fragmented, blocky crust has been lifted upward, while also slipping sideways like the plates along the San Andreas Fault do.

As Southern California's pile-up continues, the plate movements that build up seismic stress on the San Andreas are also putting stress on the long Santa Cruz-Catalina Ridge and Ferrelo Faults

And there is no reason to believe that those faults and others in the Borderlands can't rupture in the same manner as the San Andreas, said Legg.