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Sun, 25 Aug 2019
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Earthquakes

Seismograph

Shallow 6.1 magnitude earthquake hits off Amatignak Island, Alaska

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Most important Earthquake Data:

Magnitude : 6.1

Local Time (conversion only below land) : Unknown

GMT/UTC Time : 2019-05-23 08:45:19

Depth (Hypocenter) : 27.79 km

Bizarro Earth

Largest underwater eruption ever recorded in the Indian Ocean

Underwater Volcano
© CNRS/IPGP-UNIVERSITÉ DE PARIS/IFREMER/BRGM
Multibeam sonar waves, reflecting off the sea floor near the French island of Mayotte, reveal the outline of an 800-meter-tall volcano (red) and a rising gas-rich plume.
Last week, Marc Chaussidon, director of the Institute of Geophysics in Paris (IPGP), looked at seafloor maps from a recently concluded mission and saw a new mountain. Rising from the Indian Ocean floor between Africa and Madagascar was a giant edifice 800 meters high and 5 kilometers across. In previous maps, there had been nothing. "This thing was built from zero in 6 months!" Chaussidon says.

His team, along with scientists from the French national research agency CNRS and other institutes, had witnessed the birth of a mysterious submarine volcano, the largest such underwater event ever witnessed. "We have never seen anything like this," says IPGP's Nathalie Feuillet, leader of an expedition to the site by the research vessel Marion Dufresne, which released its initial results last week.

The quarter-million people living on the French island of Mayotte in the Comoros archipelago knew for months that something was happening. From the middle of last year they felt small earthquakes almost daily, says Laure Fallou, a sociologist with the European-Mediterranean Seismological Centre in Bruyères-le-Châtel, France. People "needed information," she says. "They were getting very stressed, and were losing sleep."

The authorities knew little more. Mayotte has a seismometer, but triangulating the source of the rumblings would require several instruments, and the nearest others are several hundred kilometers away in Madagascar and Kenya. A serious scientific campaign started only in February, when Feuillet and her team placed six seismometers on the ocean bottom 3.5 kilometers down, close to the activity.

Info

New study gives more detailed picture of Earth's mantle

Earth's Mantle
© iStock/Getty Images Plus
The chemical composition of the Earth's mantle is a lot more variable and diverse than previously thought, a new study has revealed.

According to a new analysis of cores drilled through the ocean crust, the mantle is made up of distinct sections of rock each with different chemical make-ups.

The chemical composition of the mantle has been notoriously difficult to determine with a high degree of certainty because it is largely inaccessible.

Scientists have traditionally relied on lava that erupts on the ocean floor to give them some idea of what the mantle is made up of, and so far studies have suggested that it's chemically mostly the same everywhere on the planet.

However in their new study, published in Nature Geoscience, the team of researchers led by scientists at Cardiff University have studied the very first minerals that begin to form when lava first makes contact with the crust at mid-ocean ridges.

Seismograph

Magnitude 6.8 earthquake hits east of New Caledonia, says USGS

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An earthquake with a magnitude of 6.8 was recorded in the South Pacific east of New Caledonia, the US Geological Survey (USGS) said today, but there were no immediate reports of damage or tsunami warnings.

The quake was recorded 179 km (111 miles) east of Tadine in the Loyalty Islands at a depth of 14 km (9 miles), the USGS said.

Source: Reuters

Seismograph

Shallow 6.0-magnitude earthquake hits Papua New Guinea

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An earthquake with a magnitude of 6.0 has struck 12 km south-west of Taron, in the South Pacific nation of Papua New Guinea on Saturday, according to U.S. Geological Survey.

The earthquake which occurred at 8:37 am local time was initially determined to be at 4.579 degrees south latitude and 153.006 degrees east longitude at a depth of 27 km.

No Tsunami warning has been issued at this time.

Seismograph

6.2-magnitude earthquake shakes El Salvador, Nicaragua

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The western coast of Central America is considered to be a seismically active zone, as it lies in an area where the Cocos plate rubs against the Caribbean plate.

Authorities in the Central American nation of El Salvador have reported a 6.2-magnitude earthquake, according to the nation's Ministry of Environment and Natural Resources.

The earthquake had its epicentre off the coast of the La Union department, about 200 kilometres southeast of the capital San Salvador.



Meanwhile, the United States Geological Survey reported a 5.7-magnitude tremor off Nicaragua.

Seismograph

Powerful shallow magnitude 7.5 earthquake hits Papua New Guinea, tsunami alert canceled

The epicenter
© Google
The epicenter
A powerful earthquake measuring 7.5 struck off Papua New Guinea on late Tuesday night, causing a tsunami warning that was later canceled, officials and residents say. There are reports of damage and power outages.

The earthquake, which struck at 11:58 p.m. local time on Tuesday, was centered in waters off the remote island of New Ireland, about 44 kilometers (27 miles) northwest of Kokopo on New Britain.

The U.S. Geological Survey put the magnitude at 7.5, down from an initial estimate of 7.7 from the Pacific Tsunami Warning Center. It said the quake struck 10 kilometers (6 miles) below the seabed, which is very shallow.

Seismograph

Strong M6.1 earthquake hits Panama but no initial reports of casualties

Panama earthquake
© USGS
The 6.1 magnitude earthquake struck at 3.24pm ET Sunday about 4 miles southeast of Plaza de Caisan, Panama, at a depth of 23 miles
A 6.1 magnitude earthquake hit Panama on Sunday near the border with Costa Rica, the U.S. Geological Survey said, but there were no immediate reports of damage or casualties.

The quake struck at a depth of 37 km (23 miles) in the far west of the country and the closest town was Santa Cruz, about 5 km away, it said.

There was no tsunami alert issued from the Pacific Tsunami Warning Center, and USGS said there was a low likelihood of casualties and damage.

In November 2017 a 6.5-magnitude quake on the Pacific coast of Costa Rica left buildings swaying in the capital San Jose and contributed to the deaths of two people who had heart attacks.

Farther north, two months earlier in September 2017 a 7.1-magnitude earthquake killed more than 300 people in Mexico.

Seismograph

Magnitude 6.3 earthquake hits near Miyazaki in southwestern Japan

Earthquake in Miyazaki, Japan
© USGS
The U.S. Geological Survey says a magnitude 6.3 earthquake hit near Miyazaki in southwestern Japan
The U.S. Geological Survey says a magnitude 6.3 earthquake hit near Miyazaki in southwestern Japan.

The agency says the earthquake struck at 8:48 a.m. Friday and had an epicenter 39 kilometers (24 miles) southeast of Miyazaki, a city of about 400,000.

The earthquake had a depth of 23 kilometers (14 miles.)

The Japan Times reports that Kyushu Electric Power Co. says no abnormalities were reported at the nearby Sendai nuclear power plant in Kagoshima Prefecture.

The Times also reports that nation's weather agency did not issue a tsunami warning.

Seismograph

7.2 magnitude earthquake hits Papua New Guinea [Update]

PNG quake
© USGS
The 7.2-magnitude earthquake was reported by USGS

Quake strikes eastern edge of mountainous country


A 7.2 magnitude earthquake has struck near Papua New Guinea, the United States Geological Survey (USGS) has said.

The quake struck 33km north west of the town of Bulolo in the early hours of Tuesday morning.

The epicentre of the strong quake was 127 km (79 miles) below the surface, the USGS said, in a region at the eastern edge of the mountainous country.

Comment: More information on the quake:
Its epicentre was 33 kilometers from the town of Bulolo at 2119 GMT according to the agency. It has a population of some 16,000. The nearest population centre is Lae, Morobe, 66km from the epicentre, with 76,000 residents.

The fire department in Lae said no one had yet called in to report damage or injuries so far following the quake. Social media photos out of Lae show stock strewn over the floors of supermarkets and clinics, though there appears to be little structural damage.

The Moresby-based National Disaster Management office said there had been no immediate reports of damage but news from the quake zone could take time to trickle in.

"We are awaiting assessments," a spokesman told AFP.



Christopher Lam was in Lae, about 100km north of Bulolo, said the rumble was audible.

"It was big. You can hear it. Got stuff thrown around in the house and the power is now cut off," he tweeted, alongside a video that showed his home rattling.

The PNG Power Ltd has issued a statement saying several of its power plants in the area of Ramu and Baiune had been knocked offline due to moving machinery, minor damage to power houses and damaged transformers.

The USGS automated assessment predicts a 65 per cent chance of zero fatalities, and just 4 per cent odds for there being up to one hundred. Economic losses are expected to be minimal.

But a similar 7.5 earthquake last year buried homes under landslides, killing some 125 people. It took several days for news of the tragedy to trickle out of PNG's remote countryside.

According to the Richter Scale, a 7-magnitude quake is equivalent to the detonation of 20 billion kilograms of dynamite and can cause serious damage to building foundations and underground pipes.