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Mon, 25 Mar 2019
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Earthquakes

Seismograph

6.6-magnitude quake hits 134 km southeast of L'Esperance Rock, New Zealand

earthquake
An earthquake of 6.6 magnitude jolted 134 km southeast of L'Esperance Rock, New Zealand on Wednesday, the U.S. Geological Survey (USGS) said.

The epicenter, with a depth of 46.0 km, was initially determined to be at 32.2 degrees south latitude and 177.8 degrees west longitude.

Seismograph

M6.2 earthquake jolts eastern Hokkaido, Japan

Hokkaido quake map
© USGS
The epicentre, with a depth of 10km, was initially determined to be at a 41.9336 degrees north latitude and 146.9481 degrees east longitude.
A magnitude 6.2 earthquake shook the eastern part of Japan's northernmost prefecture of Hokkaido on the afternoon of March 2, the Japan Meteorological Agency (JMA) said.

There were no immediate reports of casualties, and no tsunami warning was issued.

The quake, which struck at 12:23 p.m., registered a 4 on the 7-point Japanese seismic intensity scale in the northern Nemuro district and the town of Shibetsu, eastern Hokkaido, and a 3 in extensive areas of the Tokachi, Nemuro and Kushiro districts, according to the JMA.

The focus of the temblor was about 10 kilometers below the seabed off the Nemuro Peninsula.

Bizarro Earth

The last megaquake that rocked the Pacific Northwest

Cascadia Subduction Zone
© American Geoscience Institute
Screenshot of a graphic showing the Cascadia Subduction Zone.
Red cedar "ghost forests," a Japanese villager's handwritten notes, and Native American oral histories: They all offered clues that led scientists to precisely date the last megaquake that rocked the Pacific Northwest.

It occurred on Jan. 26, 1700.

Unraveling the clues was similar to being a detective investigating a "not-so-ancient geological crime," U.S. Geological Survey scientist Brian Atwater said during a presentation to a full house at LCC's Health and Science lecture hall Wednesday night.

But "there's an edge to this story," he said. "It's a frightening thing. ... The effects of the tsunami are not so pretty."

That is because the next quake could come at any time, though they recur on average every 500 years or so. But the intervals are highly variable, and researchers estimate that there's a 10 percent chance the region will be hit with the next magnitude 8 or larger earthquake within the next 50 years.

Whenever it occurs, it will shake the ground for several minutes from Vancouver Island to Northern California and churn up tsunamis that swamp coastal communities. Thousands may die, and the region's highway and utility infrastructure and thousands of buildings will collapse, geologists say.

Atwater is a pioneer whose research helped determine that giant "subduction zone" earthquakes have occurred in the Pacific Northwest in the past and will do so again.

Seismograph

Earthquake 7.0 magnitude hits Peru, no reports of injuries

earthquake
An earthquake with a magnitude of 7.0 struck southeastern Peru on Friday but there were no immediate reports of injuries or damage.

It hit in the Andes region in a sparsely populated area.

The US Geological Survey said the epicentre was at a depth of 257 kilometres (160 miles). The agency said most big quakes in South America occur at a maximum depth of 70 kilometres.

The quake hit at 0850 GMT about 27 kilometres northeast of the town of Azangaro, near the border with Bolivia.

Comment: Massive M7.5 earthquake strikes Ecuador-Peru border


Seismograph

Unusual earthquake swarm in Surrey, UK - Fracking 'exploration' began a year ago

earthquake swarm

The earthquake was recorded at a magnitude of 3.0, the British Geological Survey said
One of the largest earthquakes since a "swarm" of tremors began in the area last year has been felt in Surrey and parts of Sussex.

The quake occurred about 2km below the surface near Newdigate, the British Geological Survey (BGS) said.

The tremor was felt at 03:42 GMT and measured 3.1, making it the biggest earthquake of the current "swarm".

One resident of Redhill said his house was shaking for between four and five seconds.

Gatwick Airport confirmed tremors had been felt overnight in the terminals, but a spokesman said operations had not been affected.

Comment: A resident in Surrey comments that she has lived in the area for 47 years and that she had never experienced an earthquake before fracking exploration began:

And Surrey isn't the only area of the UK where fracking induced earthquakes are causing serious concern, in Blackpool the obvious correlation between fracking and earthquakes has resulted in the operations being shutdown, albeit temporarily: Fracking causes strongest quake yet at new site in UK

See also:


Seismograph

Massive M7.5 earthquake strikes Ecuador-Peru border

7.7 quake peru-ecuador
A massive earthquake has rocked Ecuador at the border with Peru.

The magnitude 7.7 quake has been felt across both countries.

Comment: Some early tweets reporting on the quake:






An aftershock of M5.5 is being reported:



See also:


Seismograph

Powerful 6.4 magnitude earthquake strikes Papua New Guinea

PNG quake
© Google, EMSC, TW/SAM
The country is located in the so-called Ring of Fire where a large number of earthquakes and volcanic eruptions occur.

The 6.4-magnitude quake was reported at around 14:35 GMT with the epicentre located 47 km from the city of Namatanai, New Ireland. There is no official information about any victims or damage caused by the earthquake at the moment.

The report comes just a few months after another powerful quake struck 148 km (92 miles) south of the island of Rabaul.


Bizarro Earth

Mountains buried 400 miles underground 'could be bigger than Everest'

Underground mountains
© Princeton University
A study by Princeton scientists into the boundary between the upper and lower mantle of the Earth have surprisingly found topography potentially 'rougher' than any mountain on Earth. They are located at a boundary 410 miles (600 kilometers) straight down into the Earth from the planet's surface.
An underground 'mountain' has been discovered that lies 410 miles beneath the Earth's surface that's taller than Everest.

A study by Princeton scientists into the boundary between the upper and lower mantle of the Earth have surprisingly found ridges and clefts that are potentially rougher than anything on Earth.

They are located at a boundary 410 miles (600 kilometers) straight down into the earth from the planet's surface.

Dr Wenbo Wu, one of the geophysicists on the paper said: 'In other words, stronger topography than the Rocky Mountains or the Appalachians is present at the 660-km boundary'.

Using wave data from a 8.2 magnitude earthquake in Bolivia, mountains and other topography were discovered on the base of the boundary.

The earthquake was the second-largest deep earthquake ever recorded and took place in 1994.

The most powerful waves on the planet come from giant earthquakes, that can generate shock waves which travel through the Earth's core to the other side of the planet in all directions and back again.

The data from the shock waves allow data scientists to study deep into the Earth by modelling wave data on the kind of topography that could have caused it to scatter in such a way.

Seismograph

Shallow 6.2 magnitude earthquake hits northern Mid-Atlantic Range

earthquake
An earthquake measuring 6.2 on the Richter Scale struck northern Mid-Atlantic Range region on Thursday (local time).

The quake hit at a depth of 10 km and took place at 7:57 pm, according to United States Geological Survey (USGS).

No tsunami warning has been issued so far.

The Mid-Atlantic Ridge is a mid-ocean ridge located along the floor of the Atlantic Ocean.

In the North Atlantic, the ridge separates the Eurasian and North American plates, and in the South Atlantic, it separates the African and South American plates.

Source: ANI

Seismograph

Deadly Indonesian earthquake was rare ultra-powerful supershear event

Indonesian earthquake in 2018
© Dita Alangkara/AP/REX/Shutterstock
A seismic boom contributed to the devastation of the Indonesian earthquake in 2018.
The Indonesian earthquake that impacted Sulawesi island in September 2018 was a rare ultra-powerful, superfast supershear event, according to new research out of NASA, UCLA, and more. The 7.5-magnitude earthquake caused an unexpected tsunami, the disaster ultimately claiming more than 1,500 lives and causing extreme damage. Using satellite images, researchers determined that the 7.5 Palu quake was one of fewer than 15 known supershear events.

The earthquake struck on September 28, 2018, with a steady rupture speed of 9,171MPH, according to NASA, which says the primary shock lasted for nearly one minute. This was an unusually fast speed compared to the typical 5600 to 6700MPH speeds most earthquakes present. In addition, and thanks to satellite images, the researchers found that the earthquake resulted in the fault - measuring 93 miles in length - had slipped by around 16ft.

The supershear event's rapid speed caused stronger shaking on the ground than would have resulted from a slower earthquake. Helping put this into perspective, the study's co-author Lingsen Meng explained via NASA, "The intense shaking is similar to the sonic boom associated with a supersonic jet."