A Massive ‘Blob’ of Rock Stretching Under Asia Might Be Triggering Hundreds of Earthquakes

The Hindu Kush mountain range — which stretches about 500 miles (800 kilometers) along the border of Afghanistan and Pakistan — shudders with more than 100 earthquakes at a magnitude of 4.0 or greater every year. The area is one of the most seismically active spots in the world, especially for intermediate-depth quakes (tremors forming between 45 and 190 miles, or 70 and 300 km, below the planet’s surface). And yet, scientists aren’t sure why.

The mountains don’t sit on a major fault line, where high earthquake activity is expected, and the region is many miles away from the slow-motion crash zone where the Eurasian and Indian tectonic plates are steadily colliding. So, what’s the deal with this mountain earthquake epidemic?

A new study published April 17 in the journal Tectonics may have an answer to the mystery quakes of the Hindu Kush — and, like all great geologic mysteries, it involves blobs.

According to the study, the Hindu Kush mountains may owe their incredible seismic reputation to a long “blob” of rock slowly dripping away from the range’s subterranean underbelly and into the hot, viscous mantle below. Like a lone water droplet pulling away from the edge of a faucet, the 100-mile-deep (150 km) blob of mountain may be pulling away from the continental crust at a rate as fast as 4 inches (10 centimeters) per year — and this subterranean stress could be triggering earthquakes, the authors of the new study wrote.

The researchers discovered the troublesome blob after collecting several years’ worth of earthquake observations near the Hindu Kush mountains. They saw that the quakes formed in a pattern, creating what looked like a “round patch” of seismic activity on the planet’s surface, study co-author Rebecca Bendick, a geophysicist at the University of Montana in Missoula, told the website Eos.org. Those quakes also formed along a clear vertical axis, beginning between 100 and 140 miles (160 and 230 km) below the continent, and were most common deeper down, where the solid continental crust meets the hot, viscous upper mantle. Here, the researchers wrote, is where the slowly-stretching blob is strained the most.

All of these observations were consistent with a blob of solid rock slowly dripping into the gooey underworld below — a hypothesis that has previously been used to explain similar seismic activity underneath the Carpathian Mountains in central Europe. According to the researchers, the Hindu Kush blob likely began dripping no earlier than 10 million years ago, and continues to stretch downward nearly 10 times faster than the surface of the mountains move, as the Indian and Eurasian plates collide.

If accurate, these results may be more evidence that geophysical forces beyond just the subduction of tectonic plates can send earthquakes rattling through the planet.

Tsunami Alert Issued, 7.5 Quake Hits New Guinea

A powerful earthquake struck Papua New Guinea late Tuesday evening, triggering a tsunami alert for coastal areas up to 1,000 kilometers (620 miles) away.

The U.S. Geological Survey said the quake measured magnitude 7.5 and was located 45 kilometers (28 miles) northeast of Kokopo, a remote town with a population of about 26,000. It was centered at a relatively shallow depth of 10 kilometers (6 miles), it said.

Shallow earthquakes tend to cause more damage on the Earth’s surface, but the USGS estimated that damage and injuries would be low because of the area’s sparse population.

The U.S. Pacific Tsunami Warning Center said tsunami waves of up to 1 meter (3.3 feet) were possible along coastal areas up to 1,000 kilometers (620 miles) from the epicenter, including Papua New Guinea and the nearly Solomon Islands. It later said the tsunami threat had largely passed and no waves had been observed, but that there were no sea level gauges in the area for measurement.

It said there was no tsunami threat to Hawaii or Guam.

Papua New Guinea is located on the eastern half of the island of New Guinea, to the east of Indonesia.

It sits on the Pacific’s “Ring of Fire,” the arc of seismic faults around the Pacific Ocean where much of the world’s earthquakes and volcanic activity occurs.

A magnitude 7.5 earthquake in February 2018 in the nation’s central region killed at least 125 people and forced another 35,000 from their homes. That quake hit areas that are remote and undeveloped, and assessments about the scale of the damage and injuries were slow to filter out.

6.1 Magnitude Earthquake In Panama Injures Two

A 6.1 magnitude earthquake rattled homes in southwest Panama on Sunday near the border with Costa Rica, damaging buildings and injuring at least two people, but there were no immediate reports of fatalities, authorities said. The quake struck some 4 miles southeast of Plaza de Caisán, Panama, at a depth of about 12 miles, the U.S. Geological Survey (USGS) reported.

Graphic shows large earthquake logo over broken earth and Richter scale reading

Panamanian authorities said there was no tsunami alert from the quake. Panama’s President Juan Carlos Varela said on Twitter that some shops and houses were damaged and that a woman was injured in the Panamanian port of Puerto Armuelles when the quake caused the ceiling of her home to cave in.

Puerto Armuelles is near the epicenter of the quake. A local police spokeswoman said some buildings were damaged, but there were no initial reports of fatalities.

Images posted on social media showed simple wooden homes that partially collapsed in rural areas, deep fissures in tightly packed beach sand and entire grocery store shelves that spilled containers of processed food and bottled beverages on the floor.

“I was in the supermarket and everything swayed,” Carla Chavez said by phone from David, the capital of Panama’s Chiriqui province near the quake’s epicenter. “Merchandise fell on the floor. Everything happened so fast.”

Panama’s National Civil Protection Service said via Twitter that walls cracked at a hospital and two supermarkets in Changuinola in Bocas del Toro province.

The USGS later pinpointed the epicenter of the quake as a few miles north of Paso Canoas in Costa Rica, right on the border with Panama. Local emergency services in Paso Canoas said they had no initial reports of damage or fatalities there.

Panama’s firefighting association said on Twitter it had received reports of the ground shaking from residents in different regions of the country, and urged calm.

Data Mining Digs Up Hidden Clues To Major California Earthquake Triggers

A powerful computational study of southern California seismic records has revealed detailed information about a plethora of previously undetected small earthquakes, giving a more precise picture about stress in the earth’s crust. A new publicly available catalog of these findings will help seismologists better understand the stresses triggering the larger earthquakes that occasionally rock the region.

“It’s very difficult to unpack what triggers larger earthquakes because they are infrequent, but with this new information about a huge number of small earthquakes, we can see how stress evolves in fault systems,” said Daniel Trugman, a post-doctoral fellow at Los Alamos National Laboratory and coauthor of a paper published in the journal Science today. “This new information about triggering mechanisms and hidden foreshocks gives us a much better platform for explaining how big quakes get started,” Trugman said.

Crunching the Numbers

Trugman and coauthors from the California Institute of Technology and Scripps Institution of Oceanography performed a massive data mining operation of the Southern California Seismic Network for real quakes buried in the noise. The team was able to detect, understand, and locate quakes more precisely, and they created the most comprehensive earthquake catalog to date. The work identified 1.81 million quakes — 10 times more earthquakes occurring 10 times more frequently than quakes previously identified using traditional seismology methods.

The team developed a comprehensive, detailed earthquake library for the entire southern California region, called the Quake Template Matching (QTM) catalog. They are using it to create a more complete map of California earthquake faults and behavior. This catalog may help researchers detect and locate quakes more precisely.

The team analyzed nearly two decades of data collected by the Southern California Seismic Network. The network, considered one of the world’s best seismic systems, amasses a catalog of quakes from 550 seismic monitoring stations in the region. The SCSN catalog is based entirely on the traditional approach: manual observation and visual analysis. But Trugman says this traditional approach misses many weak signals that are indicators of small earthquakes.

Matching Templates Is Key

The team improved on this catalog with data mining. Using parallel computing, they crunched nearly 100 terabytes of data across 200 graphics processing units. Zooming in at high resolution for a 10-year period, they performed template matching using seismograms (waveforms or signals) of previously identified quakes. To create templates, they cut out pieces of waveforms from previously recorded earthquakes and matched those waveforms to patterns of signals recorded simultaneously from multiple seismic stations. Template matching has been done before, but never at this scale.

“Now we can automate it and search exhaustively through the full waveform archive to find signals of very small earthquakes previously hidden in the noise,” Trugman explained.

Applying the templates found events quake precursors, foreshocks and small quakes that had been missed with manual methods. Those events often provide key physical and geographic details to help predict big quakes. The team also identified initiation sequences that reveal how quakes are triggered.

New details also revealed three-dimensional geometry and fault structures, which will support development of more realistic models.

Recently, Trugman and Los Alamos colleagues have applied machine learning to study earthquakes created in laboratory quake machines. That works has uncovered important details about earthquake behavior that may be used to predict quakes.

“In the laboratory, we see small events as precursors to big slip events, but we don’t see this consistently in the real world. This big data template-matching analysis bridges the gap,” he said. “And now we’ve discovered quakes previously discounted as noise and learned more about their behavior. If we can identify these sequences as foreshocks in real time, we can predict the big one.”

2 Earthquakes Shake The Philippines; At Least 16 Dead

A powerful 6.4 earthquake struck the Philippines on Tuesday, the day after a different temblor took lives and collapsed buildings.

Rescuers continued to search for survivors from Monday’s quake, centered just 50 miles northwest of Manila, the capital. That quake killed at least 16 people, according to The Associated Press. So far, it appears that Tuesday’s 6.4 magnitude quake in Eastern Samar province did not cause any casualties or major damage.

Monday’s magnitude 6.1 quake struck Pampanga province, north of Manila, shortly after 5 p.m. local time. A supermarket collapsed in the municipality of Porac, killing at least five people, the AP reports. Others remain missing.

One man was reportedly pulled out alive from the supermarket’s rubble on Tuesday morning, to cheers from onlookers.

“We’re all very happy, many clapped their hands in relief because we’re still finding survivors after several hours,” Porac Councilor Maynard Lapid told the AP.

Fifteen of the dead were in Pampanga province, the state news service reported. Philippine President Rodrigo Duterte arrived in the affected area Tuesday, where he inspected the damage and was briefed on the situation.

Aurelia Daeng, 65, told Reuters that she was in her family’s drugstore when Monday’s quake struck. “It was very strong. It was our first time experiencing something like that,” she told the news service. “This one, it’s terrifying.”

Monday’s quake also shook the nation’s capital, where panicked office workers fled buildings, some in hard hats, according to Reuters.

More than 400 aftershocks continued to unsettle residents after Monday’s quake, and the government closed more than 1,600 schools in the region. Central Luzon, the area struck, is in one of the country’s most seismically active regions, home to three major faults and an oceanic trench.

Philippine seismologists said the two earthquakes were not related, the AP reports. The country is part of the “Ring of Fire,” a belt of heavy seismic activity where some 90 percent of the world’s earthquakes occur, according to the U.S. Geological Survey.

Strong Earthquake Strikes Philippines, Killing 11 People

MANILA — A powerful earthquake shook the northern Philippines on Monday, leaving at least 11 people dead in collapsed buildings, municipal and disaster relief officials said.

The Philippine Institute of Volcanology and Seismology said the quake had registered a magnitude of 6.1 and had been centered near the town of Castillejos in Zambales Province, west of Manila. It struck shortly after 5 p.m., as government offices and private businesses were closing for the day.

In the town of Porac, northwest of Manila, five people were reported crushed to death after a wall in a four-story supermarket collapsed, RJ Mago, a spokesman for the National Disaster Risk Reduction and Management Council, told a local radio station.

[One day after the deadly tremor, a powerful earthquake struck Samar, an island in the central eastern Philippines.]

He said an older woman and her granddaughter who had been injured at the supermarket had been taken to a hospital and were in good condition.

Lilia Pineda, the governor of the northern province of Pampanga, said that she had received reports that the quake had killed eight people there and had knocked out power.

“Almost all concrete electric posts in the villages of Lubao town have fallen down,” she said.

The quake was felt in varying intensities in Manila, where news outlets reported panicked workers fleeing tall office buildings. It was also intense in Malolos and Obando, north of the capital; in Lipa, a city south of Manila; and in the town of Magalang in Pampanga Province. At least 25 urban centers and provinces recorded tremors.

Renato U. Solidum Jr., an official at the Department of Science and Technology, said that although the quake had not caused extensive damage, it could produce many aftershocks.

“This earthquake is not a major earthquake, but it’s a strong earthquake,” he said, adding, “This is already far from Metro Manila but a little bit shallow so we can feel it.” Seventeen aftershocks were recorded by the state seismology institute.

Because of its location on the so-called Pacific Ring of Fire, the Philippines is prone to earthquakes and volcanic eruptions caused by the movement of tectonic plates.

In October 2013, nearly 100 people were killed after a powerful earthquake struck the central island of Bohol.

Data Mining Digs Up Hidden Clues To Major California Earthquake Triggers

A powerful computational study of southern California seismic records has revealed detailed information about a plethora of previously undetected small earthquakes, giving a more precise picture about stress in the earth’s crust. A new publicly available catalog of these findings will help seismologists better understand the stresses triggering the larger earthquakes that occasionally rock the region.

“It’s very difficult to unpack what triggers larger earthquakes because they are infrequent, but with this new information about a huge number of small earthquakes, we can see how stress evolves in fault systems,” said Daniel Trugman, a post-doctoral fellow at Los Alamos National Laboratory and coauthor of a paper published in the journal Science today. “This new information about triggering mechanisms and hidden foreshocks gives us a much better platform for explaining how big quakes get started,” Trugman said.

Crunching the Numbers

Trugman and coauthors from the California Institute of Technology and Scripps Institution of Oceanography performed a massive data mining operation of the Southern California Seismic Network for real quakes buried in the noise. The team was able to detect, understand, and locate quakes more precisely, and they created the most comprehensive earthquake catalog to date. The work identified 1.81 million quakes — 10 times more earthquakes occurring 10 times more frequently than quakes previously identified using traditional seismology methods.

The team developed a comprehensive, detailed earthquake library for the entire southern California region, called the Quake Template Matching (QTM) catalog. They are using it to create a more complete map of California earthquake faults and behavior. This catalog may help researchers detect and locate quakes more precisely.

The team analyzed nearly two decades of data collected by the Southern California Seismic Network. The network, considered one of the world’s best seismic systems, amasses a catalog of quakes from 550 seismic monitoring stations in the region. The SCSN catalog is based entirely on the traditional approach: manual observation and visual analysis. But Trugman says this traditional approach misses many weak signals that are indicators of small earthquakes.

Matching Templates Is Key

The team improved on this catalog with data mining. Using parallel computing, they crunched nearly 100 terabytes of data across 200 graphics processing units. Zooming in at high resolution for a 10-year period, they performed template matching using seismograms (waveforms or signals) of previously identified quakes. To create templates, they cut out pieces of waveforms from previously recorded earthquakes and matched those waveforms to patterns of signals recorded simultaneously from multiple seismic stations. Template matching has been done before, but never at this scale.

“Now we can automate it and search exhaustively through the full waveform archive to find signals of very small earthquakes previously hidden in the noise,” Trugman explained.

Applying the templates found events quake precursors, foreshocks and small quakes that had been missed with manual methods. Those events often provide key physical and geographic details to help predict big quakes. The team also identified initiation sequences that reveal how quakes are triggered.

New details also revealed three-dimensional geometry and fault structures, which will support development of more realistic models.

Recently, Trugman and Los Alamos colleagues have applied machine learning to study earthquakes created in laboratory quake machines. That works has uncovered important details about earthquake behavior that may be used to predict quakes.

“In the laboratory, we see small events as precursors to big slip events, but we don’t see this consistently in the real world. This big data template-matching analysis bridges the gap,” he said. “And now we’ve discovered quakes previously discounted as noise and learned more about their behavior. If we can identify these sequences as foreshocks in real time, we can predict the big one.”