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Sat, 08 Aug 2020
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Earthquakes

Bizarro Earth

Alaska rocks under 7.8M earthquake, triggers tsunami warning

Alaska Earthquake
© USGS
A tsunami warning has been issued for coastal parts of the northern US state of Alaska after the USGS confirmed a 7.8 magnitude earthquake struck at a depth of 10km, roughly 100km offshore.

The quake struck at approximately 06:12:42 (UTC). The US Tsunami Warning System raised the alarm over 'hazardous waves' due to strike coastal communities from Sand Point to Kodiak and Cold Bay.


Comment: A large aftershock of magnitude 6.1 also hit 4 minutes later.


Seismograph

Deep repeating earthquakes beneath Hawaii's Maunakea volcano surprise scientists

Seismic data from the station near Maunakea volcano

Example of 2 hours of seismic data from the station near Maunakea on April 14. The large spikes are earthquakes under Maunakea repeating every 11 minutes. The bottom waveform zooms in on 15 seconds of an individual event.
Maunakea volcano hasn't erupted in over 4,500 years, but that doesn't mean it's quiet. In fact, for decades it has been hiding one of the most unique seismic signals seen at any volcano.

Some discoveries are just serendipity. Several years ago, U.S. Geological Survey seismologists at the Hawaiian Volcano Observatory and Alaska Volcano Observatory were trying out a new method to track seismicity at Kilauea Volcano. The method scans 24-hour sections of seismometer data looking for signal similarity on many instruments. Out of curiosity, they decided to look at the rest of the Island of Hawaii to see what else they might find.

What they found came as a surprise. A study published in the journal Science in May, 2020 describes how they detected deep earthquakes beneath Maunakea that repeat every 7-12 minutes. Noise in the seismic records from wind and nearby cars, together with the small size of the individual earthquakes (magnitude 1.5), had prevented these earthquakes from being detected with the regular earthquake detection system.

The small, repeating earthquakes occur at depths of about 20-25 km (12-15 mi) directly beneath Maunakea's summit and happen every 7-12 minutes with surprising regularity. Furthermore, the repeating events can be detected going back to at least 1999. This was when a particularly quiet seismic station was installed in the saddle between Maunakea and Mauna Loa. It is very likely that the repeating earthquakes were occurring even further back in time.

Comment: See also:


Seismograph

6.0-magnitude earthquake hits Fiji region: USGS

Earthquake seismograph
An earthquake with a magnitude of 6.0 jolted Fiji region at 20:56:24 GMT on Tuesday, the U.S. Geological Survey said.

The epicenter, with a depth of 602.12 km, was initially determined to be at 20.8319 degrees south latitude and 178.5723 degrees west longitude.

Blue Planet

African continent is breaking apart, new ocean will flood over the Afar region

afar ocean
© CC BY-SA 3.0 IGO / Envisat satellite / Lake Malawi, Great Rift Valley
The Red Sea and the Gulf of Aden emerged as the result of a deep geological process that has been going on for the last 30 million years with Arabia moving away from Africa. But even these waters could soon merge into a new, yet-to-be-named ocean, as the world's hottest continent splits apart.

Something is going on underneath the African continent. It has been known for some time that the three tectonic plates, Nubian, Somali and Arabian, that lie beneath the continent's Afar region, have been very slowly peeling apart from each other. Now researchers are able to use satellite images and measurements to study the process more precisely and predict how a new ocean will soon flood the region, according to NBC News.

Comment: A BBC documentary reports:


For more recent events concerning the earth changes occurring beneath our feet, see: For insight into what may be driving this shift, SOTT radio reports: And check out SOTT's monthly report Earth Changes Summary - May 2020: Extreme Weather, Planetary Upheaval, Meteor Fireballs for the various phenomena occurring worldwide:





Seismograph

6.5-magnitude quake hits off Tonga: USGS

quake
An earthquake with a magnitude of 6.5 jolted 99 km ENE of Hihifo, Tonga at 15:32:43 GMT on Saturday, the U.S. Geological Survey said.

The epicenter, with a depth of 33.0 km, was initially determined to be at 15.5 degrees south latitude and 173.0 degrees west longitude.

Seismograph

Magnitude 5.9 earthquake hits Iquique, Chile

quake
An earthquake of a magnitude of 5.9 degrees, according to consolidated information from the National Seismological Center, was recorded at 1.40 am this Friday in the Tarapacá Region.

The epicenter of the tremor was located 4 kilometers northeast of Alto Hospicio, while its hypocenter was recorded at a depth of 77 kilometers.

In that commune, in addition to Iquique and the town of La Tirana, the movement reached a degree VI intensity on the Mercalli scale.


Seismograph

7.0-magnitude earthquake hits off Papua New Guinea coast

PNG quake map
© United States Geological Survey / screenshot

A 7.0-magnitude earthquake has struck the region of eastern Papua New Guinea at a depth of 85.5km, the US Geological Survey reported. A tsunami warning was issued.

The Pacific Tsunami Warning Center put out an alert for "hazardous waves" for coastal area within 300km of the epicenter of the quake, which took place around 8pm Pacific Time.

The National Weather Service later reported that the North American coastline was not in danger.

The USGS initially reported the quake as magnitude 7.3, but later downgraded it to 7.0.

There have been no reports of damage or casualties so far.

Info

Powerful eruptions on the Sun might trigger earthquakes says new research

False Color Composite
© SOHO
This false-color composite of the Sun was created using ultraviolet images taken by the Solar and Heliospheric Observatory (SOHO) satellite.
Through decades of research, scientists have learned that large, powerful earthquakes commonly occur in groups, not in random patterns. But exactly why has so far remained a mystery. Now, new research, published July 13 in Scientific Reviews, asserts the first strong — though still disputed — evidence that powerful eruptions on the Sun can trigger mass earthquake events on Earth.

"Large earthquakes all around the world are not evenly distributed ... there is some correlation among them," says Giuseppe De Natale, research director at the National Institute of Geophysics and Volcanology in Rome and co-author of the new study. "We have tested the hypothesis that solar activity can influence the worldwide [occurrence of earthquakes]."

Seismograph

Iceland earthquake swarm reaches over 10,000 quakes, largest in 40 years

earthquake graph
© Phil McCarten / Reuters
An ongoing earthquake swarm in Iceland has now reached over 10,000 quakes since it began on June 19. This is the biggest swarm to hit the Tjörnes Fracture zone in the north of the country in almost half a century, and experts are unsure what is causing it.

The earthquake swarm to the northeast of the town of Siglufjörður is ongoing. Experts with the Iceland Meteorological Office (IMO) said that of the 10,000 earthquakes, three had measured magnitude 5 or above. The largest, magnitude 5.8, hit around 18 miles from Siglufjörður. "Seismic activity if still ongoing and there are chances of more earthquakes of this magnitude occurring in the area," the IMO said in a statement.

Earthquakes have been felt in the area surrounding the swarm. Some of the larger quakes have been felt as far as Reykjavíc, 125 miles away.

Kristín Jónsdóttir, Earthquakes Hazards Officer for the IMO, previously told Newsweek the swarm was the largest recorded in the Tjörnes Fracture Zone in the past 40 years. "It is very difficult to say [when the swarm will end]," she said. "The behavior is episodic, we record hundreds of earthquakes in a few hours and then it becomes quiet and all of a sudden it starts again. The last swarm in 2012 was ongoing for a few weeks. Let's hope we only have a few weeks to go."

The IMO said that between June 22 and 28, over 3,300 earthquakes were recorded in the region. Of these, 2,800 were west of the Húsavík-Flatey Islands fault.

Seismograph

The sixth sense of animals: An early warning system for earthquakes?

Professor Martin Wikelski attaches accelerometers to the collars of farm animals
© Max Planck Institute of Animal Behavior
Professor Martin Wikelski attaches accelerometers to the collars of farm animals.
Even today, nobody can reliably predict when and where an earthquake will occur. However, eyewitnesses have repeatedly reported that animals behave unusually before an earthquake. In an international cooperation project, researchers from the Max Planck Institute of Animal Behavior in Konstanz/Radolfzell and the Cluster of Excellence Center for the Advanced Study of Collective Behavior at the University of Konstanz, have investigated whether cows, sheep, and dogs can actually detect early signs of earthquakes.

To do so, they attached sensors to the animals in an earthquake-prone area in Northern Italy and recorded their movements over several months. The movement data show that the animals were unusually restless in the hours before the earthquakes. The closer the animals were to the epicenter of the impending quake, the earlier they started behaving unusually. The movement profiles of different animal species in different regions could therefore provide clues with respect to the place and time of an impending earthquake.

Experts disagree about whether earthquakes can be exactly predicted. Nevertheless, animals seem to sense the impending danger hours in advance. For example, there are reports that wild animals leave their sleeping and nesting places immediately before strong quakes and that pets become restless. However, these anecdotal accounts often do not stand up to scientific scrutiny because the definition of unusual behavior is often too unclear and the observation period too short. Other factors could also explain the behavior of the animals.