Friday, April 19, 2013

PLANETARY TREMORS: 6.0 Magnitude Earthquake Strikes Off Kuril Islands!

April 19, 2013 - KURIL ISLANDS - An earthquake of preliminary magnitude 6.0 struck today east of the Kuril Islands, according to the U.S. Geological Survey (USGS).


Map of earthquake location east of Kuril Islands on Friday, April 19.
CREDIT: USGS

The temblor's epicenter was 82 miles (133 kilometers) southeast of Severo-Kuril'sk, Russia and 206 miles (333 km) south of Vilyuchinsk, Russia. It originated 11.6 miles (18.6 km) deep and struck at 19:58:40 UTC (06:58:40 a.m. local time, April 20), the USGS reports.

Earthquakes of this size are considered major and can cause significant damage, especially with poorly built structures. Even well designed buildings can be damaged or, in some cases, destroyed depending on the severity of the quake and a building’s proximity to the epicenter. Earthquakes of this size are sometimes followed by significant aftershocks.

But the damage caused by any single event depends on the quake's depth, proximity to populated areas, building standards in the region, as well as the type of earthquake. - Live Science.


USGS earthquake shakemap intensity.



Tectonic Summary - Seismotectonics of the Kuril-Kamchatka Arc
The April 19, 2013 M 7.2 earthquake ENE of Kuril’sk, Russia, occurred as a result of oblique normal faulting at intermediate depths within the subducting lithosphere of the Pacific plate. At the latitude of this earthquake, the Pacific plate converges with the North America plate (and the smaller Okhotsk microplate) towards the west-northwest at a velocity of approximately 82 mm/yr, and subducts beneath the Kuril Islands at the Kuril-Kamchatka trench, some 160 km to the southeast of the April 19 event. The depth of this earthquake, and its oblique-faulting mechanism, indicate that it involved intraplate faulting within the subducting slab, rather than being an interplate thrust event on the shallower seismogenic zone between the two tectonic plates.

The Kuril-Kamchatka arc has frequent moderate-to-large earthquakes, and has hosted over three-dozen M 6.5+ events within 250 km of the April 19 earthquake over the past 40 years. None are known to have caused shaking-related fatalities. The largest of these was the November 2006 M 8.3 interplate thrust event, approximately 200 km to the east of the April 19 earthquake. However, while the Pacific slab is seismically active in this region to depths of almost 700 km, just one of these nearby M 6.5+ events has occurred at depths greater than 70 km – a M 6.7 event in October 1994, 130 km to the southwest.

Intermediate depth (70 – 300km) and deep-focus (depth greater than 300 km) earthquakes are distinguished from shallow earthquakes (depth less than 70 km) by the nature of their tectonic setting, and are in general much less hazardous than their shallow counterparts, though they may be felt at great distances from their epicenters.


USGS historic seismicity for the region.

The Kuril-Kamchatka arc extends approximately 2,100 km from Hokkaido, Japan, along the Kuril Islands and the Pacific coast of the Kamchatka Peninsula to its intersection with the Aleutian arc near the Commander Islands, Russia. It marks the region where the Pacific plate subducts into the mantle beneath the Okhotsk microplate, part of the larger North America plate. This subduction is responsible for the generation of the Kuril Islands chain, active volcanoes located along the entire arc, and the deep offshore Kuril-Kamchatka trench. Relative to a fixed North America plate, the Pacific plate is moving towards the northwest at a rate that increases from 75 mm/year near the northern end of the arc to 83 mm/year in the south.

Plate motion is predominantly convergent along the Kuril-Kamchatka arc with obliquity increasing towards the southern section of the arc. The subducting Pacific plate is relatively old, particularly adjacent to Kamchatka where its age is greater than 100 Ma. Consequently, the Wadati-Benioff zone is well defined to depths of approximately 650 km. The central section of the arc is comprised of an oceanic island arc system, which differs from the continental arc systems of the northern and southern sections. Oblique convergence in the southern Kuril arc results in the partitioning of stresses into both trench-normal thrust earthquakes and trench-parallel strike-slip earthquakes, and the westward translation of the Kuril forearc. This westward migration of the Kuril forearc currently results in collision between the Kuril arc in the north and the Japan arc in the south, resulting in the deformation and uplift of the Hidaka Mountains in central Hokkaido.

The Kuril-Kamchatka arc is considered one of the most seismically active regions in the world. Deformation of the overriding North America plate generates shallow crustal earthquakes, whereas slip at the subduction zone interface between the Pacific and North America plates generates interplate earthquakes that extend from near the base of the trench to depths of 40 to 60 km. At greater depths, Kuril-Kamchatka arc earthquakes occur within the subducting Pacific plate and can reach depths of approximately 650 km.

This region has frequently experienced large (Magnitude greater than 7) earthquakes over the past century. Since 1900, seven great earthquakes (M8.3 or larger) have also occurred along the arc, with mechanisms that include interplate thrust faulting, and intraplate faulting. Damaging tsunamis followed several of the large interplate megathrust earthquakes. These events include the February 3, 1923 M8.4 Kamchatka, the November 6,1958 M8.4 Etorofu, and the September 25, 2003 M8.3 Hokkaido earthquakes. A large M8.5 megathrust earthquake occurred on October 13, 1963 off the coast of Urup, an island along the southern Kuril arc, which generated a large tsunami in the Pacific Ocean and the Sea of Okhotsk, and caused run-up wave heights of up to 4-5 m along the Kuril arc. The largest megathrust earthquake to occur along the entire Kurile-Kamchatka arc in the 20th century was the November 4, 1952 M9.0 event. This earthquake was followed by a devastating tsunami with run-up wave heights as high as 12 m along the coast of Paramushir, a small island immediately south of Kamchatka, causing significant damage to the city of Severo-Kurilsk.

On October 4,1994, a large (M8.3) intraplate event occurred within the subducted oceanic lithosphere off the coast of Shikotan Island causing intense ground shaking, landslides, and a tsunami with run-up heights of up to 10 m on the island.

The most recent megathrust earthquake in the region was the November 15, 2006 M8.3 Kuril Island event, located in the central section of the arc. Prior to this rupture, this part of the subduction zone had been recognized as a seismic gap spanning from the northeastern end of the 1963 rupture zone to the southwestern end of the 1952 rupture. Two months after the 2006 event, a great (M8.1) normal faulting earthquake occurred on January 13, 2007 in the adjacent outer rise region of the Pacific plate. It has been suggested that the 2007 event may have been caused by the stresses generated from the 2006 earthquake. - USGS.

BOSTON WARZONE: Bomb Suspect Dead, Another On The Run - Suspects Are Chechens, Bombs Strapped To Suspect's Chest, Explosions, Gunfire, Lockdown, Residents Told To Stay Inside, Public Transit Suspended, Campuses Close, MIT Cop Shot Dead, Massive Manhunt Underway,...!

April 19, 2013 - UNITED STATES - The two suspects in the Boston Marathon bombings led police on a wild and deadly chase through the suburbs here early Friday morning that ended in the death of one of the suspects as well as a campus police officer; the other suspect remained at large while hundreds of police officers conduct a manhunt through Watertown, about five miles west of downtown Boston.

Investigators believe that that both of the suspects were Chechens, a law enforcement official said Friday morning.

The Boston region was in the grip of a security emergency as hundreds of police officers conducted a manhunt through the normally tranquil Boston suburbs.


A police spokesman confirmed that explosives were involved.
    Julio Cortez/Associated Press

Gov. Deval Patrick has suspended service on all public transit services in the MBTA system in Boston, including the “T” subway, buses and commuter trains. The authorities asked all residents of the towns of Watertown, Newton, Waltham and Cambridge to stay home and stay indoors. Watertown was locked down early Friday morning, with no one allowed to leave their homes and no businesses allowed to open.

Several area colleges announced the cancellation of classes on Friday, including M.I.T., Harvard, Boston University, Boston College, Emerson College, Northeastern University and Suffolk University.

“This situation is grave, we are here to protect public safety,” said Col. Tim Alben of the Massachusetts State Police.

“We believe these are the same individuals that were responsible for the bombing on Monday at the Boston Marathon,” Mr. Alben said. “We believe that they’re responsible for the death of an MIT police officer and the shooting of an MBTA officer.”


Police officers converged in Watertown early Friday.
Matt Rourke/Associated Press

In the course of the chase, the suspects shot and killed a campus police officer at the Massachusetts Institute of Technology and severely wounded a transit police officer, police said.

Edward Davis, the Boston Police Commissioner, told reporters early Friday morning that the two men involved in the chase were the suspects identified Thursday by the F.B.I. as responsible for setting the explosives at Monday’s marathon that killed three people and injured more than 170 others.

He also said that one of the suspects, wearing the black hat in the F.B.I. photos, was dead and that the other suspect, in the white hat, was still on the loose.

  The Boston Police Department released this
image of the suspect at large on Friday.
Boston Police Dept.
Early Friday, a virtual army of heavily armed law enforcement officers was still going through houses in Watertown one by one in a search for the second suspect. Police had blocked off a 20-block residential area and urged residents emphatically to stay inside their homes and not answer their doors.

“We are concerned about securing that area and making sure that this individual is taken into custody,” Mr. Davis said. “We believe this to be a terrorist. We believe this to be a man who’s come here to kill people, and we need to get him in custody.”

With gunfire ricocheting around the tranquil neighborhood, residents were later told to go into their basements and stay away from windows.

The pursuit began after 10 p.m. Thursday when two men robbed a 7/11 near Central Square in Cambridge. A security camera caught a man identified as one of the suspects, wearing a gray hoodie.

About 10:30, police received reports that a campus security officer at M.I.T. was shot while he sat in his police cruiser. He was found with multiple gunshot wounds, according to a statement issued by Middlesex Acting District Attorney Michael Pelgro, Cambridge Police Commissioner Robert Haas, and MIT Police Chief John DiFava. The officer was taken to Massachusetts General Hospital, where he was pronounced dead.

A short time later, police received reports of an armed carjacking of a Mercedes SUV by two males in the area of Third Street in Cambridge, the statement said. “The victim was carjacked at gunpoint by two males and was kept in the car with the suspects for approximately a half hour,” the statement said. He was later released, uninjured, at a gas station on Memorial Drive in Cambridge.

Police immediately began to search for the vehicle and pursued it into Watertown. During the chase, “explosive devices were reportedly thrown from car by the suspects,” the statement said, and the suspects and police exchanged gunfire in the area of Dexter and Laurel streets.


The police searched a street with guns drawn.
Matt Rourke/Associated Press

A Watertown resident, Andrew Kitzenberg, 29, said he looked out his third-floor window to see two young men of slight build in jackets engaged in “constant gunfire” with police officers. A police SUV “drove towards the shooters,” he said, and was shot at until it was severely damaged. It rolled out of control, Mr. Kitzenberg said, and crashed into two cars in his driveway.

The two shooters, he said, had a large, unwieldy bomb that he said looked “like a pressure cooker.”

“They lit it, still in the middle of the gunfire, and threw it. But it went 20 yards at most.” It exploded, he said, and one of the two men ran toward the gathered police officers. He was tackled, but it was not clear if he was shot, Mr. Kitzenberg said.

The explosions, said another resident, Loretta Kehayias, 65, “lit up the whole house. I screamed. I’ve never seen anything like this, never, never, never.”

Meanwhile, the other young man, said Mr. Kitzenberg, got back into the SUV, turned it toward officers and “put the pedal to the metal.” The car “went right through the cops, broke right through and continued west.”


A bomb squad truck arrived at the scene.
Craig Ruttle/Associated Press

The two men left “a few backpacks right by the car, and there is a bomb robot out there now.” Police had told residents to stay away from their windows, he said.

During this exchange, an MBTA police officer was seriously injured and taken to the hospital.

At the same time, one of the suspects was critically injured with multiple gunshot wounds and taken to Beth Israel Deaconess Hospital in Boston, where he was pronounced dead at 1:35 a.m. The authorities were investigating whether the suspect who was killed had an improvised explosive device strapped to his body, two law enforcement officials said.

A doctor who works at Beth Israel, and who lived in the area of the chase and shoot-out, said he was working at home around 1 a.m. when he heard the wailing sirens. He said at a news conference at Beth Israel that he recognized that something was wrong and alerted his emergency room to prepare for something. - NY Times.

WATCH: 1 Boston Suspect Dead, Manhunt Underway for 2nd.



WATCH: Dead Suspect Died of Blast and Gunshot Wounds.



WATCH: Boston police: one bombing suspect remains on run.



WATCH: FBI Releases Photos of Boston Marathon Suspects.



PLANETARY TREMORS: Global Seismic Uptick - Magnitude 7.0 Earthquake Strikes Off Japan In The Kuril Islands!

April 19, 2013 - KURIL ISLANDS - A 7.0-magnitude earthquake has struck in seas off far northern Japan and far eastern Russiabut but no damage was expected.

The Japan Meteorological Agency said sea changes were possible. No tsunami warnings have been issued.


USGS earthquake map and location.

The tremor struck around midday in the Pacific Ocean at a relatively shallow depth of 10 kilometres. The US Geological Survey measured a stronger 7.2 magnitude.

Japan and Russia both claim some of the sparsely populated islands in the remote region.

The epicentre was 58 kilometres east-northeast of Kuril'sk, Russia, and 528 kilometres northeast of Nemuro, Japan.

The nearest land is the volcanic islands of Urup, Iturup and Sumushir. Hokkaido officials said the islands were not under Japanese control.

The area is about 1,500 kilometres northeast of Tokyo.

The quake was felt in Hokkaido and much of the northern island of Japan. It was also reportedly felt in Tokyo.

"We have received no reports of damage so far," a spokesman at the Hokkaido police said, adding there were no reports of injuries. - News Australia.



USGS earthquake shakemap intensity.

Tectonic Summary - Seismotectonics of the Kuril-Kamchatka Arc
The April 19, 2013 M 7.2 earthquake ENE of Kuril’sk, Russia, occurred as a result of oblique normal faulting at intermediate depths within the subducting lithosphere of the Pacific plate. At the latitude of this earthquake, the Pacific plate converges with the North America plate (and the smaller Okhotsk microplate) towards the west-northwest at a velocity of approximately 82 mm/yr, and subducts beneath the Kuril Islands at the Kuril-Kamchatka trench, some 160 km to the southeast of the April 19 event. The depth of this earthquake, and its oblique-faulting mechanism, indicate that it involved intraplate faulting within the subducting slab, rather than being an interplate thrust event on the shallower seismogenic zone between the two tectonic plates.

The Kuril-Kamchatka arc has frequent moderate-to-large earthquakes, and has hosted over three-dozen M 6.5+ events within 250 km of the April 19 earthquake over the past 40 years. None are known to have caused shaking-related fatalities. The largest of these was the November 2006 M 8.3 interplate thrust event, approximately 200 km to the east of the April 19 earthquake. However, while the Pacific slab is seismically active in this region to depths of almost 700 km, just one of these nearby M 6.5+ events has occurred at depths greater than 70 km – a M 6.7 event in October 1994, 130 km to the southwest.

Intermediate depth (70 – 300km) and deep-focus (depth greater than 300 km) earthquakes are distinguished from shallow earthquakes (depth less than 70 km) by the nature of their tectonic setting, and are in general much less hazardous than their shallow counterparts, though they may be felt at great distances from their epicenters.


USGS historic seismicity for the region.

The Kuril-Kamchatka arc extends approximately 2,100 km from Hokkaido, Japan, along the Kuril Islands and the Pacific coast of the Kamchatka Peninsula to its intersection with the Aleutian arc near the Commander Islands, Russia. It marks the region where the Pacific plate subducts into the mantle beneath the Okhotsk microplate, part of the larger North America plate. This subduction is responsible for the generation of the Kuril Islands chain, active volcanoes located along the entire arc, and the deep offshore Kuril-Kamchatka trench. Relative to a fixed North America plate, the Pacific plate is moving towards the northwest at a rate that increases from 75 mm/year near the northern end of the arc to 83 mm/year in the south.

Plate motion is predominantly convergent along the Kuril-Kamchatka arc with obliquity increasing towards the southern section of the arc. The subducting Pacific plate is relatively old, particularly adjacent to Kamchatka where its age is greater than 100 Ma. Consequently, the Wadati-Benioff zone is well defined to depths of approximately 650 km. The central section of the arc is comprised of an oceanic island arc system, which differs from the continental arc systems of the northern and southern sections. Oblique convergence in the southern Kuril arc results in the partitioning of stresses into both trench-normal thrust earthquakes and trench-parallel strike-slip earthquakes, and the westward translation of the Kuril forearc. This westward migration of the Kuril forearc currently results in collision between the Kuril arc in the north and the Japan arc in the south, resulting in the deformation and uplift of the Hidaka Mountains in central Hokkaido.

The Kuril-Kamchatka arc is considered one of the most seismically active regions in the world. Deformation of the overriding North America plate generates shallow crustal earthquakes, whereas slip at the subduction zone interface between the Pacific and North America plates generates interplate earthquakes that extend from near the base of the trench to depths of 40 to 60 km. At greater depths, Kuril-Kamchatka arc earthquakes occur within the subducting Pacific plate and can reach depths of approximately 650 km.

This region has frequently experienced large (Magnitude greater than 7) earthquakes over the past century. Since 1900, seven great earthquakes (M8.3 or larger) have also occurred along the arc, with mechanisms that include interplate thrust faulting, and intraplate faulting. Damaging tsunamis followed several of the large interplate megathrust earthquakes. These events include the February 3, 1923 M8.4 Kamchatka, the November 6,1958 M8.4 Etorofu, and the September 25, 2003 M8.3 Hokkaido earthquakes. A large M8.5 megathrust earthquake occurred on October 13, 1963 off the coast of Urup, an island along the southern Kuril arc, which generated a large tsunami in the Pacific Ocean and the Sea of Okhotsk, and caused run-up wave heights of up to 4-5 m along the Kuril arc. The largest megathrust earthquake to occur along the entire Kurile-Kamchatka arc in the 20th century was the November 4, 1952 M9.0 event. This earthquake was followed by a devastating tsunami with run-up wave heights as high as 12 m along the coast of Paramushir, a small island immediately south of Kamchatka, causing significant damage to the city of Severo-Kurilsk.

On October 4,1994, a large (M8.3) intraplate event occurred within the subducted oceanic lithosphere off the coast of Shikotan Island causing intense ground shaking, landslides, and a tsunami with run-up heights of up to 10 m on the island.

The most recent megathrust earthquake in the region was the November 15, 2006 M8.3 Kuril Island event, located in the central section of the arc. Prior to this rupture, this part of the subduction zone had been recognized as a seismic gap spanning from the northeastern end of the 1963 rupture zone to the southwestern end of the 1952 rupture. Two months after the 2006 event, a great (M8.1) normal faulting earthquake occurred on January 13, 2007 in the adjacent outer rise region of the Pacific plate. It has been suggested that the 2007 event may have been caused by the stresses generated from the 2006 earthquake. - USGS.