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Earthquakes


Ambulance

Update: Taiwan earthquake kills 23, more than 130 trapped under collapsed building rubble

© Wally Santana/AP
Rescuers search for dozens missing in the collapsed apartment building in Tainan on Sunday
At least 23 have died in the quake in Tainan as the city's mayor admitted it would be 'very difficult' to reach 100 still trapped deep under a collapsed building

Rescuers in the southern Taiwanese city of Tainan were fighting against the clock on Sunday to save more than 100 people still trapped beneath rubble of an apartment block 24 hours after a strong earthquake shook the island.

A 20-year-old man was pulled alive from of the wreckage on Sunday but the city's mayor admitted that emergency teams face a "very difficult" challenge to rescue dozens of other people who remain trapped.

At least 23 people were killed when the 6.4-magnitude quake struck early on Saturday morning, many of them in a collapsed 16-storey apartment complex which contained almost 100 homes packed with families gathering for the Chinese new year.

"Of the 132 people desperately waiting for rescue, 103 people are buried very deep, there's no way to get to them direct, it's very difficult," said Tainan mayor William Lai on Sunday.


Comment: See also:


Bizarro Earth

Multiple buildings collapse in Taiwan 6.4 earthquake

© perfectfdn / Instagram
Multiple buildings, including a residential tower, have collapsed after a powerful 6.4 magnitude earthquake struck southern Taiwan early on Saturday. Authorities in the affected city have formed an emergency response center.

A building has half collapsed in Tainan as a result of the quake, with fire brigades now on their way to the site, Liu Shih-chung, Tainan City Government official, told Reuters.

At least four buildings have collapsed as a result of the earthquake.

"Four buildings have collapsed in Tainan City area. Search and rescue is underway and no casualties have been reported at this moment," Lin Kuan-cheng, spokesman for the National Fire Agency, told AFP.

Bizarro Earth

Southern Taiwan hit by 6.4 earthquake causing extensive damage, people trapped inside buildings

© t4ttoo / Instagram
Southern Taiwan was hit was hit by a magnitude 6.4 earthquake early Saturday, with heavy damage reported. Rescue crews are trying to save people feared to be trapped inside a collapsed building in the city of Tainan.

05 February 2016

22:18 GMT

Tainan City has been hit by flooding as the result of broken water lines in some areas, according to local media reports.

22:16 GMT

At least two injuries have been reported as a result of falling debris in the Huwei Township of Yunlin County, BNO news reports.

Info

New technology lets scientists locate underwater landslide that triggered deadly 1964 Alaskan tsunami

© U.S. Geological Survey
In the photo above, a section of Kodiak, Alaska, is in ruins after the massive tsunami that followed the Great Alaska Earthquake in March 1964.
Five decades after the nation's most powerful earthquake hit Alaska, scientists have pinpointed the underwater slide that triggered some of the deadliest tsunami waves produced by the shaking.

Using modern technology to map the floor of Prince William Sound, scientists from the U.S. Geological Survey and other organizations have found the landslide behind the tsunamis that killed about a third of the people in the Alutiiq village of Chenega, the service said on Monday.

Twenty-three of the village's 75 residents perished within minutes of the magnitude-9.2 earthquake that struck in 1964, making Chenega one of the communities hardest hit by the event. The village was nearly leveled and later rebuilt at a different site with a slightly different name, Chenega Bay.

In the immediate aftermath of the earthquake, scientists speculated that underwater landslides produced the waves that struck Chenega, the USGS said. A USGS technical report on the earthquake that was published in 1969 cited "localized waves of unknown origin" as the source of the most destruction. "The local waves, and combinations of local waves and subaqueous slides, caused most of the earthquake related fatalities in Alaska," that report said.

But the bathymetric technology of the time allowed for study of the seafloor only to the depth of about 180 meters, or 330 feet, the USGS said. Modern surveys conducted with multibeam sonar technology and a seismic-reflection system revealed a big complex of underwater slides that had occurred at much lower depths, the USGS said.

The findings of the USGS-led project are described in a study published online in the journal Earth and Planetary Science Letters.

"What makes this slide unusual is that much of the material that slid was at a water depth of 250 to 350 meters," or 820 to 1150 feet, Peter Haeussler, a USGS geologist based in Anchorage and a co-author of the study, said in a statement released by the survey. "The deeper initiation depth made it particularly good at generating a tsunami."

Comment: Remembering the great Alaskan earthquake and tsunami: Alaska, March 1964


Bizarro Earth

Research: Dehydration of mineral lawsonite could trigger intermediate depth earthquakes in some subduction zones

© Hirth Lab / Brown University
The mineral lawsonite undergoes brittle failure at high temperature and pressure, as evidenced by the cracks seen in the sample above. That brittleness could trigger earthquakes in subduction zones where lawsonite is present.
Geologists from Brown University may have finally explained what triggers certain earthquakes that occur deep beneath the Earth's surface in subduction zones, regions where one tectonic plate slides beneath another.

Subduction zones are some of the most seismically active areas on earth. Earthquakes in these spots that occur close to the surface can be devastating, like the one that struck Japan in 2011 triggering the Fukushima nuclear disaster. But quakes also occur commonly in the subducting crust as it pushes deep below the surface -- at depths between 70 and 300 kilometers. These quakes, known as intermediate depth earthquakes, tend to be less damaging, but can still rattle buildings.

Intermediate depth quakes have long been something of a mystery to geologists.

"They're enigmatic because the pressures are so high at that depth that the normal process of frictional sliding associated with earthquakes is inhibited," said Greg Hirth, professor of earth, environmental, and planetary sciences at Brown. "The forces required to get things to slip just aren't there."

Bizarro Earth

Magnitude 6.8 earthquake rattles northeastern Taiwan

An earthquake measuring 6.8 on the Richter Scale occurred off the coast of northeastern Taiwan at 10:19 p.m. Tuesday, the Central Weather Bureau reported shortly after the temblor.

The quake's epicenter was located at sea about 185.4 kilometers east of Keelung City Hall in northern Taiwan at a depth of 212.7 km, the bureau said.

The strongest tremors, which had an intensity of 3 on Taiwan's 0-7 seismic intensity scale, were felt in Nan'ao in Yilan County and Yenliao in Hualian County.

Taichung, Nantou County, Taitung County and Hsinchu County recorded an intensity of 2, while an intensity of 1 was reported in Taipei, New Taipei and Taoyuan, the bureau said.

Attention

Rare earthquake shakes residents of Maine, US

© Google Maps
The location of the temblor that reached 3.3 on the Richter scale on Feb.2.
At 6:56 a.m., residents on the east coast of Maine got a wake up call from nature.

A magnitude 3.3 earthquake hit 5 miles to the northeast of Eastport's shore, but residents thought it felt a lot closer than that.

Luckily, there wasn't much damage, but it gave people a good rattle.

The earthquake was detected coming from the waters between Maine and Canada's coasts. Residents from Charlotte and Perry and as far as Machias reported they heard and felt it. Some people experienced minor damage like falling household objects up to 10 miles from the center of the quake. Early risers even saw waves coming from the epicenter in the water. A magnitude 3.3 earthquake is still considered a minor one, but to some who lived close by, it was anything but.

"The only thing I could think of was the house blowing up," said one Eastport resident.

"There were some things falling off the shelves and it sounded like the house was going to crack in half," said another Eastport resident.

A worker on the pier said, "a short time later was a big wave rolling in. Just one rogue wave."

Arrow Up

Second earthquake hits Cornwall, UK within a week

A second earthquake has hit Cornwall in a week - leaving residents a little shaken by the minor tremor.

The British Geological Survey confirmed a signal at 12.04pm between Falmouth and Helston.

The data is now due to be analysed to determine its strength.

Kim Kimber, who lives near Falmouth, said: "Initially thought it might be thunder but there was not enough cloud. It felt wrong too.

"The whole house shook and the windows were rattling. I felt the vibration through the floor.

"If we lived near a quarry I might have thought they were blasting but nearest live quarry is a couple of miles away."

Last week, an earlier earthquake struck parts of Cornwall - sending a low rumble through houses around the area.

But far from any fears of a major seismic shift, perhaps splitting Cornwall from the rest of mainland Britain, the quake measured only 0.8 on the Richter Scale.

Attention

Strong magnitude 6.6 shake near the Kermadec Islands triggered 'ghost quakes' in North Island, New Zealand, but why?

© Massey University
Tuesday's earthquake was centred near the Kermadec's Raoul Island, about 1000km northeast of New Zealand.
The magnitude 6.6 quake that struck off the coast of the North Island on Tuesday was widely felt and triggered false reports of shakes in New Zealand.

It is not uncommon for earthquakes to confuse seismic readings as energy from tremors travels large distances.

These "ghost quakes" register as local earthquakes when the GNS Science system starts to receive data.

© John Ristau
Seismic graphs show the earthquake waves at 8am on Tuesday detected by the northernmost seismographs.
Let's dive right in to the world of ghost earthquakes.

What happened on Tuesday?

A large magnitude 6.6 quake centres about 850 kilometres north of Whakatane at a depth of 360km.

The epicentre was near the Kermadec Islands and the Kermadec Trench.

Bizarro Earth

6.6 magnitude earthquake strikes north of New Zealand

© USGS
The location of the quake - deep quakes off the coast were often recorded by Geonet's automatic system as multiple quakes.
A 6.6 magnitude earthquake 1100km off the North Island was responsible for the tremors that shook New Zealanders this morning.

Geonet seismologist John Ristau said the tremors felt in Bay of Plenty, Tararua and Canterbury were not official earthquakes.

There had been reports that a 5.3 magnitude quake was recorded 35 km south of Murupara and that 5.0 magnitude quake struck 20 km north west of Pongaroa.

A third quake was said to have hit 15km south-west of Amberley.

The shakes weren't official earthquakes but ripple effects of a 6.6. earthquake near Raoul Island.

Geonet received more than 500 reports of people who had felt shakes, Mr Ristau said.

There would be few aftershocks because the earthquake was so deep, he said.