Archive | October 17, 2016
A SECOND fault line running parallel to San Andreas has just been identified
The San Andreas Fault. Credit: US Geological Survey
Just days after a cluster of more than 200 small earthquakes shook the Salton Sea area of Southern California, scientists have found evidence of a second fault line that runs parallel to the massive San Andreas Fault – one of the state’s most dangerous fault lines.
The new fault appears to run right through the 56-km-long Salton Sea in the Colorado Desert, to the west of the San Andreas Fault. Now that we know it’s there, seismologists will be forced to reassess earthquake risk models for the greater Los Angeles area.
“This previously unidentified fault represents a new hazard to the region and holds significant implications for fault models … and, consequently, models of ground-motion prediction and southern San Andreas Fault rupture scenarios,” the team from the Scripps Institution of Oceanography and the Nevada Seismological Laboratory reports.
Now known as the Salton Trough Fault, the newly mapped fault has been hidden for all this time because it’s submerged beneath the Salton Sea – a vast, salty rift lake that formed as a result of all the tectonic activity in the area.
The team had to use an array of instruments, including multi-channel seismic data, ocean-bottom seismometers, and a surveying method called light detection and ranging (LiDAR), to precisely map fault inside several sediment layers both in and surrounding the lakebed.
“The location of the fault in the eastern Salton Sea has made imaging it difficult, and there is no associated small seismic events, which is why the fault was not detected earlier,” says Scripps geologist Neal Driscoll.
Oddly enough, the fact that we now know there’s an extra fault line running parallel to the San Andreas Fault doesn’t necessarily mean the area is more prone to earthquakes than we originally thought.
It might actually solve the mystery of why the region has been experiencing LESS earthquakes than expected.
As the team explains, recent research has revealed that the region has experienced magnitude-7 earthquakes roughly every 175 to 200 years for the last 1,000 years.
But that’s not been the case more recently. In fact, a major rupture on the southern portion of the San Andreas Fault has not occurred in the last 300 years, and researchers think the region is long overdue for a major quake.
Now they have to figure out what role the Salton Trough Fault could have played in all that.
“The extended nature of time since the most recent earthquake on the Southern San Andreas has been puzzling to the earth sciences community,” said one of the Nevada team, seismologist Graham Kent.
“Based on the deformation patterns, this new fault has accommodated some of the strain from the larger San Andreas system, so without having a record of past earthquakes from this new fault, it’s really difficult to determine whether this fault interacts with the southern San Andreas Fault at depth or in time.”
A map of the new fault line, STF. Credit: Sahakian et. al.
On Monday morning, ominous rumblings started to emanate from deep underneath the Salton Sea, and then a ‘swarm’ of small earthquakes – three measuring above magnitude 4 – ruptured at the nearby Bombay Beach.
The ruptures continued for roughly 24 hours, with more than 200 small earthquakes having been recorded in the area.
These small earthquakes – or temblors – were not very severe, but this is just the third time since records began in 1932 that the area has experienced such an event. And this one had more earthquakes than both the 2001 and 2009 events.
The event caused the US Geological Survey to increase the estimated risk of a magnitude 7 or greater earthquake in the next week from to between 1 in 3,000 and 1 in 100. To put that in perspective, without any quake swarms, the average risk for the area sits at around 1 in 6,000.
Fortunately, the increased risk now appears to have passed, and according to the Los Angeles Times, California governor’s Office of Emergency Service just announced that the earthquake advisory period is now officially over.
Of course, for those living in the area, it’s cold comfort, because the southern San Andreas Fault is still “locked, loaded, and ready to go”. Let’s hope the discovery of the Salton Trough Fault will make it easier for seismologists to at least predict when that will happen.
Courtesy of sciencealert.com
MEGA DIP SPIKES ON THE WEAK MAGNETOSPHERE @ APPROX 18:45, 19:00 HRS UTC
**VERY URGENT**
MEGA DIP SPIKES ON THE WEAK MAGNETOSPHERE @ APPROX 18:45, 19:00 HRS UTC. FURTHER EARTHQUAKES, VOLCANO ACTIVITY & ADVERSE WEATHER PATTERNS WILL BE GREATLY INFLUENCED BY THE COSMIC RAYS STRIKING THE EARTH’S CORE
***BE ALERT***
At least 21 die in massive floods in central Vietnam; alert issued for typhoon Sarika
The Vietnam government said on Sunday that at least 21 people died and eight are still missing in four central provinces in the past week due to massive floods, as the country braces for Typhoon Sarika.
The government said the typhoon is expected to hit the Quang Binh province by Wednesday. Fifteen of the victims were from this province.
Typhoon Sarika was moving towards the South China Sea before it barreled into northern Philippine provinces on Sunday. The local weather bureau said they are monitoring the typhoon closely and that it could cross the eastern boundary by Monday.
The Deputy Prime Minister of Vietnam Trinh Dinh Dung urged the authorities on Sunday to reinforce key infrastructure projects in 22 coastal provinces and to decide evacuation plans.
He assured that the government would provide food relief in flooded areas.
According to a Vietnam Television (VTV) broadcast, he said: “We need to focus on searching for the missing”.
The state-run VTV warned its viewers that many reservoirs were nearly full and could burst at any time. It also showed footage of people stranded on the roofs of their houses.
A government report showed that around 500,000 people have been already displaced and more than 100,000 houses were submerged and damaged by floods.
The disaster officials in the Philippines said the typhoon unleashed heavy rainfall and strong winds on northern rice-growing regions but there were no confirmed casualty reports.
They added that initially the total damage to farm crops, mostly rice and corn, was estimated at 53.5 million pesos (S$1.5 million).
According to the weather forecasters, as typhoon Sarika was moving out of the country it packed winds of up to 120kmh on Sunday afternoon.
The authorities said almost 2,552 families, or 12,496 individuals had been pre-emotively evacuated before the storm caused landfall early on Sunday. 160 domestic and international flights and a number of ferry services were cancelled due to Sarika.
The weather bureau has reduced the level of storm warning signals, but it said the authorities are keeping a close watch on Haima, which is apparently the next weather disturbance.
“It’s still far, out of the Philippine Area of Responsibility, but it’s now on the level of a storm. Over time, while travelling over water, it gains strength, so that’s our next concern,” Ricardo Jalad, the executive director of the National Disaster Risk Reduction and Management Council told The Straits Times.
Jalad said Typhoon Sarika did not cause “that serious” damage compared with what had been initially expected. However, he said there were several reports of landslides and flooding in some areas.
Referring to the town where typhoon Sarika caused landfall, he said: “We were focused on Baler, but local officials were able to conduct pre-emptive evacuation, so there was no casualty.”
Courtesy of ibtimes.sg
MAGNITUDE 3.2 FYR OF MACEDONIA
http://www.emsc-csem.org/Earthquake/earthquake.php?id=537651
Subject To Change
Depth: 5 km
Distances: 133 km SE of Skopje, FYR of Macedonia / pop: 475,000 / local time: 15:02:34.2 2016-10-17
9 km N of Star Dojran, FYR of Macedonia / pop: 3,400 / local time: 15:02:34.2 2016-10-17
MAGNITUDE 4.3 GREECE ALBANIA BORDER REGION
http://www.emsc-csem.org/Earthquake/earthquake.php?id=537631
Subject To Change
Depth: 2 km
Distances: 190 km SE of Tirana, Albania / pop: 375,000 / local time: 14:15:05.3 2016-10-17
17 km NW of Ioánnina, Greece / pop: 64,100 / local time: 15:15:05.3 2016-10-17
6 km NW of Rodotópion, Greece / pop: 1,200 / local time: 15:15:05.3 2016-10-17
MAGNITUDE 3.0 PYRENEES
http://www.emsc-csem.org/Earthquake/earthquake.php?id=537498
Subject To Change
Depth: 5 km
Distances: 127 km W of Andorra la Vella, Andorra / pop: 20,500 / local time: 10:43:34.6 2016-10-17
48 km S of Tarbes, France / pop: 52,200 / local time: 10:43:34.6 2016-10-17
8 km S of Luz-Saint-Sauveur, France / pop: 1,100 / local time: 10:43:34.6 2016-10-17
MAGNITUDE 4.5 SOUTHERN QINGHAI, CHINA
http://www.emsc-csem.org/Earthquake/earthquake.php?id=537353
Subject To Change
Depth: 30 km
Distances: 799 km NE of Thimphu, Bhutan / pop: 98,700 / local time: 14:24:38.6 2016-10-17
524 km NE of Lhasa, China / pop: 119,000 / local time: 16:24:38.6 2016-10-17
281 km NW of Qamdo, China / pop: 86,300 / local time: 16:24:38.6 2016-10-17
MAGNITUDE 4.5 EASTERN XIZANG
http://www.emsc-csem.org/Earthquake/earthquake.php?id=537470
Subject To Change
Depth: 10 km
Distances: 581 km NW of Dayan, China / pop: 1,138,000 / local time: 15:54:43.4 2016-10-17
568 km NE of Itānagar, India / pop: 45,000 / local time: 13:24:43.4 2016-10-17
26 km NW of Qamdo, China / pop: 86,300 / local time: 15:54:43.4 2016-10-17
MAGNITUDE 4.7 SOUTHERN QINGHAI, CHINA
http://www.emsc-csem.org/Earthquake/earthquake.php?id=537468
Subject To Change
Depth: 10 km
Distances: 791 km NE of Thimphu, Bhutan / pop: 98,700 / local time: 13:33:35.7 2016-10-17
516 km NE of Lhasa, China / pop: 119,000 / local time: 15:33:35.7 2016-10-17
273 km NW of Qamdo, China / pop: 86,300 / local time: 15:33:35.7 2016-10-17
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