Sumatra quake: Tremors felt in Singapore; authorities urge calm
Police and the Singapore Civil Defence Force urge those in Singapore to remain calm after a 7.8-magnitude quake hit southwest Sumatra on Wednesday night. Tremors were subsequently felt in parts of Singapore.
Posted 02 Mar 2016 22:57 Updated 02 Mar 2016 23:20
SINGAPORE: Police have urged members of the public to remain calm after tremors were felt in Singapore, following a 7.8-magnitude earthquake that hit Indonesia on Wednesday night (Mar 2).
In an advisory, police said the Meteorological Services confirmed the earthquake hit southwest Sumatra - about 1,237km from Singapore - at about 8.49pm on Wednesday. Tremors were subsequently felt in parts of Singapore from 8.53pm. Both the Police and the Singapore Civil Defence Force received several calls from the public reporting these tremors, it said.
If members of the public are inside a building and feel tremors, police advise them to:
i) Take cover under a sturdy table or furniture
ii) Keep away from items made of glass or any hanging object
iii) Do not use the lift
iv) Do not use any naked light, in case there is a gas leak
Those out in the open should minimise their movement and stay away from buildings, street lights and utility wires, police added. After the vibrations have stopped, they should:
i) Stay away from any exposed electrical cables, hanging glass objects
ii) Report any gas leakage
iii) Help the injured, call SCDF if the injuries are significant
iv) Report any incidents or issues of law and order to Police
v) Tune in to the radio for updates, according to police
The Singapore Civil Defence Force similarly asked those in Singapore to not be alarmed, and posted information on what to do in the event of tremors.
TREMORS FELT IN BISHAN, EAST COAST, SENG KANG, ANG MO KIO
Residents in Singapore reported feeling tremors in areas including Bishan, Punggol, East Coast, Seng Kang and Ang Mo Kio. However, Singapore is unlikely to be affected by the earthquake, said the National Environment Agency.
A Katong resident, who only wanted to be identified as Ms Amanda, said she felt tremors from her 12th-floor apartment shortly after the quake struck, at about 9.05pm.
“I was lying down reading a book when suddenly I felt like the ground was moving side to side. I thought I was feeling tired, but my mum saw our lamps outside shaking, so we decided to evacuate,” she told Channel NewsAsia.
Amanda said there were about 15 residents gathered downstairs of her condominium. Her family of six stayed at the ground floor for about half an hour.
“We live quite high up, and we have two dining lamps which won’t shake if it’s just (strong) wind. It’s happened before during an earthquake as well,” said Ms Amanda of her family’s decision to self-evacuate from their apartment.
They eventually returned to their home at 9.30pm. “We just wanted to be safe first. We headed downstairs and saw other people, so that confirmed it,” she said.
A resident in Kembangan who lives in an apartment also reported feeling strong tremors from the quake. "I felt like I was swaying from left to right. On a scale of 1 to 5, I'll rate (the movement) at the 2.5 to 3," said Ms Jazryl Lee.
Indonesia, especially Aceh, was badly hit by the Indian Ocean tsunami in 2004. The country straddles the so-called "Pacific Ring of Fire", a highly seismically active zone, where different plates on the earth's crust meet and create a large number of earthquakes and volcanoes.
- CNA
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Showing posts with label earthquake. Show all posts
Showing posts with label earthquake. Show all posts
Wednesday, March 2, 2016
Monday, March 21, 2011
Reports of sustained uptime in Japan continue
Reports of sustained uptime in Japan continue
No major data center outages reported following disaster
Published 18th March, 2011 by Yevgeniy Sverdlik
Many data center companies in Japan continued reporting throughout the week following a devastating earthquake and tsunami off Japan’s northeastern coast that their data centers continued normal operations. Ample fuel had been secured for many facilities’ backup generators to address rolling blackouts implemented by energy providers.
Jiro Fukuda of the Japan Data Center Council wrote in an email to DatacenterDynamics that there had not been any reports of major damage to data centers as of 17 March. “The Internet and other network services are being provided as usual,” he wrote.
“The discussion about the maintenance of long-term service continuance has already started [among] data center service providers,” Fukuda added.
JDDC is a data center industry consortium, consisting of representatives from the private sector, academia and the government.
Data center services provider Telehouse released a statement on 17 March, saying all 21 of its data centers in Japan were operational, including one in Sendai – the area most severely affected by the disaster.
The company said the data centers will stay operational throughout periodic three-hour rolling black-outs that have been implemented by Tohoku-Electric Power and Tokyo Electric Power.
“All facilities have a minimum 24-hour fuel supply plus regularly scheduled refueling (natural gas and/or diesel) and are expected to continue normal operations,” a Telehouse statement read.
HP and IBM, two large multinationals that act as both IT vendors and providers of data center services, also said their data centers continued normal operations.
HP CEO Leo Apotheker said during a press conference in San Francisco on 14 March that the company’s infrastructure in Japan “has not been really touched.”
IBM Japan spokesman Kazuhiro Kaneko wrote in an email to DatacenterDynamics on 15 March that “all IBM data centers have been working normally even just after the earthquake, and we keep delivering our services to the clients.”
Some services provided by the telecom Internet Initiative Japan were partly unavailable because of service disruptions experienced by some access-network carriers. IIJ said on 17 March that its own infrastructure continued operating as usual.
“IIJ's backbone network and service facilities are operating without disruption,” the company said.
IIJ services that were partially unavailable because of access-network carriers’ problems were Wide Area Network, Line management, FiberAccess, DSL and Mobile services.
Some of the company’s managed services, including security services, were affected by a “chaotic distribution channel”, delaying deliveries of network equipment.
Services affected by delivery disruptions include mobile, managed router, Internet-LAN, managed VPN Pro, managed firewall, IIJ DDoS and network intrusion detection, among others.
Delays in arrival of network-support staff could also play an effect on service availability, IIJ said.
- wong chee tat :)
No major data center outages reported following disaster
Published 18th March, 2011 by Yevgeniy Sverdlik
Many data center companies in Japan continued reporting throughout the week following a devastating earthquake and tsunami off Japan’s northeastern coast that their data centers continued normal operations. Ample fuel had been secured for many facilities’ backup generators to address rolling blackouts implemented by energy providers.
Jiro Fukuda of the Japan Data Center Council wrote in an email to DatacenterDynamics that there had not been any reports of major damage to data centers as of 17 March. “The Internet and other network services are being provided as usual,” he wrote.
“The discussion about the maintenance of long-term service continuance has already started [among] data center service providers,” Fukuda added.
JDDC is a data center industry consortium, consisting of representatives from the private sector, academia and the government.
Data center services provider Telehouse released a statement on 17 March, saying all 21 of its data centers in Japan were operational, including one in Sendai – the area most severely affected by the disaster.
The company said the data centers will stay operational throughout periodic three-hour rolling black-outs that have been implemented by Tohoku-Electric Power and Tokyo Electric Power.
“All facilities have a minimum 24-hour fuel supply plus regularly scheduled refueling (natural gas and/or diesel) and are expected to continue normal operations,” a Telehouse statement read.
HP and IBM, two large multinationals that act as both IT vendors and providers of data center services, also said their data centers continued normal operations.
HP CEO Leo Apotheker said during a press conference in San Francisco on 14 March that the company’s infrastructure in Japan “has not been really touched.”
IBM Japan spokesman Kazuhiro Kaneko wrote in an email to DatacenterDynamics on 15 March that “all IBM data centers have been working normally even just after the earthquake, and we keep delivering our services to the clients.”
Some services provided by the telecom Internet Initiative Japan were partly unavailable because of service disruptions experienced by some access-network carriers. IIJ said on 17 March that its own infrastructure continued operating as usual.
“IIJ's backbone network and service facilities are operating without disruption,” the company said.
IIJ services that were partially unavailable because of access-network carriers’ problems were Wide Area Network, Line management, FiberAccess, DSL and Mobile services.
Some of the company’s managed services, including security services, were affected by a “chaotic distribution channel”, delaying deliveries of network equipment.
Services affected by delivery disruptions include mobile, managed router, Internet-LAN, managed VPN Pro, managed firewall, IIJ DDoS and network intrusion detection, among others.
Delays in arrival of network-support staff could also play an effect on service availability, IIJ said.
- wong chee tat :)
Wednesday, March 16, 2011
Japan Quake May Have Slightly Shortened Earth Days, Moved Axis, Theoretical Calculations Suggest
Japan Quake May Have Slightly Shortened Earth Days, Moved Axis, Theoretical Calculations Suggest
ScienceDaily (Mar. 15, 2011) — The magnitude 9.0 earthquake that struck Japan March 11, 2011 may have slightly shortened the length of each Earth day and shifted its axis.
Using a United States Geological Survey estimate for how the fault responsible for the earthquake slipped, research scientist Richard Gross of NASA's Jet Propulsion Laboratory, Pasadena, Calif., applied a complex model to perform a preliminary theoretical calculation of how the Japan earthquake -- the fifth largest since 1900 -- affected Earth's rotation. His calculations indicate that by changing the distribution of Earth's mass, the Japanese earthquake should have caused Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds (a microsecond is one millionth of a second).
The calculations also show the Japan quake should have shifted the position of Earth's figure axis (the axis about which Earth's mass is balanced) by about 17 centimeters (6.5 inches), towards 133 degrees east longitude. Earth's figure axis should not be confused with its north-south axis; they are offset by about 10 meters (about 33 feet). This shift in Earth's figure axis will cause Earth to wobble a bit differently as it rotates, but it will not cause a shift of Earth's axis in space -- only external forces such as the gravitational attraction of the sun, moon and planets can do that.
Both calculations will likely change as data on the quake are further refined.
In comparison, following last year's magnitude 8.8 earthquake in Chile, Gross estimated the Chile quake should have shortened the length of day by about 1.26 microseconds and shifted Earth's figure axis by about 8 centimeters (3 inches). A similar calculation performed after the 2004 magnitude 9.1 Sumatran earthquake revealed it should have shortened the length of day by 6.8 microseconds and shifted Earth's figure axis by about 7 centimeters, or 2.76 inches. How an individual earthquake affects Earth's rotation depends on its size (magnitude), location and the details of how the fault slipped.
Gross said that, in theory, anything that redistributes Earth's mass will change Earth's rotation.
"Earth's rotation changes all the time as a result of not only earthquakes, but also the much larger effects of changes in atmospheric winds and oceanic currents," he said. "Over the course of a year, the length of the day increases and decreases by about a millisecond, or about 550 times larger than the change caused by the Japanese earthquake. The position of Earth's figure axis also changes all the time, by about 1 meter (3.3 feet) over the course of a year, or about six times more than the change that should have been caused by the Japan quake."
Gross said that while we can measure the effects of the atmosphere and ocean on Earth's rotation, the effects of earthquakes, at least up until now, have been too small to measure. The computed change in the length of day caused by earthquakes is much smaller than the accuracy with which scientists can currently measure changes in the length of the day. However, since the position of the figure axis can be measured to an accuracy of about 5 centimeters (2 inches), the estimated 17-centimeter shift in the figure axis from the Japan quake may actually be large enough to observe if scientists can adequately remove the larger effects of the atmosphere and ocean from the Earth rotation measurements. He and other scientists will be investigating this as more data become available.
Gross said the changes in Earth's rotation and figure axis caused by earthquakes should not have any impacts on our daily lives. "These changes in Earth's rotation are perfectly natural and happen all the time," he said. "People shouldn't worry about them."
Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by NASA/Jet Propulsion Laboratory.
- wong chee tat :)
ScienceDaily (Mar. 15, 2011) — The magnitude 9.0 earthquake that struck Japan March 11, 2011 may have slightly shortened the length of each Earth day and shifted its axis.
Using a United States Geological Survey estimate for how the fault responsible for the earthquake slipped, research scientist Richard Gross of NASA's Jet Propulsion Laboratory, Pasadena, Calif., applied a complex model to perform a preliminary theoretical calculation of how the Japan earthquake -- the fifth largest since 1900 -- affected Earth's rotation. His calculations indicate that by changing the distribution of Earth's mass, the Japanese earthquake should have caused Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds (a microsecond is one millionth of a second).
The calculations also show the Japan quake should have shifted the position of Earth's figure axis (the axis about which Earth's mass is balanced) by about 17 centimeters (6.5 inches), towards 133 degrees east longitude. Earth's figure axis should not be confused with its north-south axis; they are offset by about 10 meters (about 33 feet). This shift in Earth's figure axis will cause Earth to wobble a bit differently as it rotates, but it will not cause a shift of Earth's axis in space -- only external forces such as the gravitational attraction of the sun, moon and planets can do that.
Both calculations will likely change as data on the quake are further refined.
In comparison, following last year's magnitude 8.8 earthquake in Chile, Gross estimated the Chile quake should have shortened the length of day by about 1.26 microseconds and shifted Earth's figure axis by about 8 centimeters (3 inches). A similar calculation performed after the 2004 magnitude 9.1 Sumatran earthquake revealed it should have shortened the length of day by 6.8 microseconds and shifted Earth's figure axis by about 7 centimeters, or 2.76 inches. How an individual earthquake affects Earth's rotation depends on its size (magnitude), location and the details of how the fault slipped.
Gross said that, in theory, anything that redistributes Earth's mass will change Earth's rotation.
"Earth's rotation changes all the time as a result of not only earthquakes, but also the much larger effects of changes in atmospheric winds and oceanic currents," he said. "Over the course of a year, the length of the day increases and decreases by about a millisecond, or about 550 times larger than the change caused by the Japanese earthquake. The position of Earth's figure axis also changes all the time, by about 1 meter (3.3 feet) over the course of a year, or about six times more than the change that should have been caused by the Japan quake."
Gross said that while we can measure the effects of the atmosphere and ocean on Earth's rotation, the effects of earthquakes, at least up until now, have been too small to measure. The computed change in the length of day caused by earthquakes is much smaller than the accuracy with which scientists can currently measure changes in the length of the day. However, since the position of the figure axis can be measured to an accuracy of about 5 centimeters (2 inches), the estimated 17-centimeter shift in the figure axis from the Japan quake may actually be large enough to observe if scientists can adequately remove the larger effects of the atmosphere and ocean from the Earth rotation measurements. He and other scientists will be investigating this as more data become available.
Gross said the changes in Earth's rotation and figure axis caused by earthquakes should not have any impacts on our daily lives. "These changes in Earth's rotation are perfectly natural and happen all the time," he said. "People shouldn't worry about them."
Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by NASA/Jet Propulsion Laboratory.
- wong chee tat :)
Sunday, March 13, 2011
Quake moved Japan by 2.4 meters
Quake moved Japan by 2.4 meters
Posted: 13 March 2011 1109 hrs
WASHINGTON: Japan's recent massive earthquake, one of the largest ever recorded, appears to have moved the island by about 2.4 meters (8 feet), the US Geological Survey said Saturday.
"That's a reasonable number," USGS seismologist Paul Earle told AFP. "Eight feet, that's certainly going to be in the ballpark."
Friday's 8.9 magnitude quake unleashed a terrifying tsunami that engulfed towns and cities on Japan's northeastern coast, destroying everything in its path in what Prime Minister Naoto Kan said was an "unprecedented national disaster."
The quake and its tectonic shift resulted from "thrust faulting" along the boundary of the Pacific and North America plates, according to the USGS.
The Pacific plate pushes under a far western wedge of the North America plate at the rate of about 3.3 inches per year, but a colossal earthquake can provide enough of a jolt to dramatically move the plates, with catastrophic consequences.
"With an earthquake this large, you can get these huge ground shifts," Earle said.
"On the actual fault you can get 20 meters (65 feet) of relative movement, on the two sides of the fault."
He said similar movements would have been seen for Chile and Indonesia.
In December 2004, a 9.1 magnitude quake off Sumatra caused a tsunami that killed an estimated 228,000 people.
An 8.8 quake off the coast of Chile in February 2010 killed more than 500.
There was not a similar ground shift in the 7.0 earthquake that devastated Haiti in February 2010, Earle said.
"A magnitude 7.0 is much smaller than the earthquake that just happened in Japan," he said. "We've had aftershocks (in Japan) larger than the Haiti earthquake."
Kenneth Hudnut, a USGS geophysicist, said experts read data including from global positioning systems to determine the extend of the shift.
"We know that one GPS station moved (eight feet), and we have seen a map from GSI (Geospatial Information Authority) in Japan showing the pattern of shift over a large area is consistent with about that much shift of the land mass," he told CNN.
- AFP/cc
- wong chee tat :)
Posted: 13 March 2011 1109 hrs
WASHINGTON: Japan's recent massive earthquake, one of the largest ever recorded, appears to have moved the island by about 2.4 meters (8 feet), the US Geological Survey said Saturday.
"That's a reasonable number," USGS seismologist Paul Earle told AFP. "Eight feet, that's certainly going to be in the ballpark."
Friday's 8.9 magnitude quake unleashed a terrifying tsunami that engulfed towns and cities on Japan's northeastern coast, destroying everything in its path in what Prime Minister Naoto Kan said was an "unprecedented national disaster."
The quake and its tectonic shift resulted from "thrust faulting" along the boundary of the Pacific and North America plates, according to the USGS.
The Pacific plate pushes under a far western wedge of the North America plate at the rate of about 3.3 inches per year, but a colossal earthquake can provide enough of a jolt to dramatically move the plates, with catastrophic consequences.
"With an earthquake this large, you can get these huge ground shifts," Earle said.
"On the actual fault you can get 20 meters (65 feet) of relative movement, on the two sides of the fault."
He said similar movements would have been seen for Chile and Indonesia.
In December 2004, a 9.1 magnitude quake off Sumatra caused a tsunami that killed an estimated 228,000 people.
An 8.8 quake off the coast of Chile in February 2010 killed more than 500.
There was not a similar ground shift in the 7.0 earthquake that devastated Haiti in February 2010, Earle said.
"A magnitude 7.0 is much smaller than the earthquake that just happened in Japan," he said. "We've had aftershocks (in Japan) larger than the Haiti earthquake."
Kenneth Hudnut, a USGS geophysicist, said experts read data including from global positioning systems to determine the extend of the shift.
"We know that one GPS station moved (eight feet), and we have seen a map from GSI (Geospatial Information Authority) in Japan showing the pattern of shift over a large area is consistent with about that much shift of the land mass," he told CNN.
- AFP/cc
- wong chee tat :)
Scientists already making discoveries in wake of Japan's temblor
Scientists already making discoveries in wake of Japan's temblor
March 12, 2011 By Eryn Brown
Friday's 8.9-magnitude temblor off the east coast of Japan ranks as one of the 10-largest earthquakes ever recorded. Though scientists have just begun to pore over the data, they have already made some surprising discoveries about one of the most quake-prone regions on Earth.
Here's what experts have learned about the earthquake thus far.
Q: What caused it?
A: The earthquake occurred because a portion of the Pacific Plate is being pushed into and underneath the North American plate, forming a so-called subduction zone that built up so much pressure it ruptured, slipping as much as 60 feet.
"This was a planetary monster," said Thomas Jordan, director of the Southern California Earthquake Center at USC.
The earthquake occurred along a patch of an undersea fault that's about 220 miles long and 60 miles wide. Because the fault broke at a shallow depth, it shifted the sea floor, triggering tsunamis throughout the Pacific Ocean.
Q: Was it a surprise?
A: Yes and no. Seismologists said the quake was larger than they thought was possible in that part of the world. "We thought about the Big One as an 8.5 or so," said Susan Hough, a seismologist at the U.S. Geological Survey in Pasadena, Calif. Such an earthquake would have been about one-third as strong as an 8.9 quake.
"But it's not like an 8.9 hit Kansas," she added. "We know Japan is an active subduction zone."
What tripped scientists up was a lack of recent activity in the area, Jordan said. The last earthquake of this magnitude along this plate boundary occurred in the year 869. Seismologists had been debating the fault's potential to break, but they had little data to go on.
"The question was whether that section had locked - accumulating strain - or was it slipping slowly," Jordan said. "We now know that this is a plate boundary that was locked."
Q: You mean there were no hints at all?
A: Brian Atwater, a USGS seismologist based in Seattle, said that Japanese GPS data collected since the 1990s showed that the coast of Japan was being pulled inland at a rate of about 25 feet per century, another indication that the plates were stuck and energy was building between them.
"That's like money in the bank in terms of producing an earthquake," he said. "The more time that passes, the more the bank account fills up. This fault had not been a big spender for a long time."
Q: There was a lot of seismic activity off Japan's coast last week, including a magnitude 7.2 quake on Wednesday. Should that have been a warning sign?
A: In hindsight, it's clear that there were foreshocks, experts said. But if the smaller quakes had petered out, they would have looked like business as usual. "It wasn't that big a deal for that part of the world," Hough said. "There's always activity going on. But those are the kind of earthquakes that happen on a weekly basis. You can't go on high alert every time this happens."
"These were foreshocks," agreed USC's Jordan, "but we couldn't have known."
Q: Should we expect more earthquakes?
A: Aftershocks in the region have been ongoing, including 10 in the first hour alone. Jordan and Hough said that these could be quite damaging and might even create another rupture along the complex system of plate boundaries that extend toward Tokyo.
It's not unusual to see far-flung increases in seismic activity after large earthquakes, Jordan said. In part, that's because the Earth oscillates after a big quake much like when a musician hits a gong, and such vibrations can change the stresses on faults "in a small way."
But Hough said there's no reason to think that this earthquake will trigger a series of other catastrophic quakes around the world. Sometimes it seems like big quakes come in clusters, but it's just a coincidence, she said: "It's not like there's some global supercluster getting out of hand."
Q: Will this change the way scientists look at earthquakes around the world?
A: It already has, by expanding the list of places where magnitude 9 "megaquakes" could happen, Hough said. "We had a sense that these couldn't happen along any subduction zone - that it took a certain geometry, a bigger zone," she said. "One lesson is that these are possible in more places than we thought."
Q: Does this change our understanding of earthquakes in Southern California and elsewhere on the West Coast?
A: Not really. The San Andreas fault is not a subduction fault. It's a strike-slip fault, where one plate moves sideways relative to the other, that is broken into two segments. Hough said that a rupture over the length of the entire 800-mile-long fault, which she believes would result in a magnitude 8.3 quake, is unlikely because there's a stretch in the middle where the fault is able to creep, releasing energy. A full break of either section of the San Andreas would result in a quake of about a magnitude 8, she estimates. The events in Japan don't alter those estimates.
Comparisons to faults in the Pacific Northwest may be more apt. There, as in Japan, the plate boundary is a subduction zone.
Q: This sounds a lot like the 9.3 earthquake that struck Sumatra in 2004, generating a tsunami that killed more than 230,000 people in 14 countries.
It's similar to that quake but significantly smaller. The stretch of the plate boundary involved in the Sumatra quake was 700 to 900 miles long, Hough said.
Q: The 1995 Kobe quake in Japan killed more than 6,000 people. Was it almost as big as this one?
A: Not even close. Its magnitude was 6.9 and its fault area was 100 times less than this quake's, Jordan said. But it was deadly because it came so close to the city of Kobe.
"Earthquakes are like real estate," he said. What matters is "location, location, location."
(c) 2011, Los Angeles Times.
Distributed by McClatchy-Tribune Information Services.
- wong chee tat :)
March 12, 2011 By Eryn Brown
Friday's 8.9-magnitude temblor off the east coast of Japan ranks as one of the 10-largest earthquakes ever recorded. Though scientists have just begun to pore over the data, they have already made some surprising discoveries about one of the most quake-prone regions on Earth.
Here's what experts have learned about the earthquake thus far.
Q: What caused it?
A: The earthquake occurred because a portion of the Pacific Plate is being pushed into and underneath the North American plate, forming a so-called subduction zone that built up so much pressure it ruptured, slipping as much as 60 feet.
"This was a planetary monster," said Thomas Jordan, director of the Southern California Earthquake Center at USC.
The earthquake occurred along a patch of an undersea fault that's about 220 miles long and 60 miles wide. Because the fault broke at a shallow depth, it shifted the sea floor, triggering tsunamis throughout the Pacific Ocean.
Q: Was it a surprise?
A: Yes and no. Seismologists said the quake was larger than they thought was possible in that part of the world. "We thought about the Big One as an 8.5 or so," said Susan Hough, a seismologist at the U.S. Geological Survey in Pasadena, Calif. Such an earthquake would have been about one-third as strong as an 8.9 quake.
"But it's not like an 8.9 hit Kansas," she added. "We know Japan is an active subduction zone."
What tripped scientists up was a lack of recent activity in the area, Jordan said. The last earthquake of this magnitude along this plate boundary occurred in the year 869. Seismologists had been debating the fault's potential to break, but they had little data to go on.
"The question was whether that section had locked - accumulating strain - or was it slipping slowly," Jordan said. "We now know that this is a plate boundary that was locked."
Q: You mean there were no hints at all?
A: Brian Atwater, a USGS seismologist based in Seattle, said that Japanese GPS data collected since the 1990s showed that the coast of Japan was being pulled inland at a rate of about 25 feet per century, another indication that the plates were stuck and energy was building between them.
"That's like money in the bank in terms of producing an earthquake," he said. "The more time that passes, the more the bank account fills up. This fault had not been a big spender for a long time."
Q: There was a lot of seismic activity off Japan's coast last week, including a magnitude 7.2 quake on Wednesday. Should that have been a warning sign?
A: In hindsight, it's clear that there were foreshocks, experts said. But if the smaller quakes had petered out, they would have looked like business as usual. "It wasn't that big a deal for that part of the world," Hough said. "There's always activity going on. But those are the kind of earthquakes that happen on a weekly basis. You can't go on high alert every time this happens."
"These were foreshocks," agreed USC's Jordan, "but we couldn't have known."
Q: Should we expect more earthquakes?
A: Aftershocks in the region have been ongoing, including 10 in the first hour alone. Jordan and Hough said that these could be quite damaging and might even create another rupture along the complex system of plate boundaries that extend toward Tokyo.
It's not unusual to see far-flung increases in seismic activity after large earthquakes, Jordan said. In part, that's because the Earth oscillates after a big quake much like when a musician hits a gong, and such vibrations can change the stresses on faults "in a small way."
But Hough said there's no reason to think that this earthquake will trigger a series of other catastrophic quakes around the world. Sometimes it seems like big quakes come in clusters, but it's just a coincidence, she said: "It's not like there's some global supercluster getting out of hand."
Q: Will this change the way scientists look at earthquakes around the world?
A: It already has, by expanding the list of places where magnitude 9 "megaquakes" could happen, Hough said. "We had a sense that these couldn't happen along any subduction zone - that it took a certain geometry, a bigger zone," she said. "One lesson is that these are possible in more places than we thought."
Q: Does this change our understanding of earthquakes in Southern California and elsewhere on the West Coast?
A: Not really. The San Andreas fault is not a subduction fault. It's a strike-slip fault, where one plate moves sideways relative to the other, that is broken into two segments. Hough said that a rupture over the length of the entire 800-mile-long fault, which she believes would result in a magnitude 8.3 quake, is unlikely because there's a stretch in the middle where the fault is able to creep, releasing energy. A full break of either section of the San Andreas would result in a quake of about a magnitude 8, she estimates. The events in Japan don't alter those estimates.
Comparisons to faults in the Pacific Northwest may be more apt. There, as in Japan, the plate boundary is a subduction zone.
Q: This sounds a lot like the 9.3 earthquake that struck Sumatra in 2004, generating a tsunami that killed more than 230,000 people in 14 countries.
It's similar to that quake but significantly smaller. The stretch of the plate boundary involved in the Sumatra quake was 700 to 900 miles long, Hough said.
Q: The 1995 Kobe quake in Japan killed more than 6,000 people. Was it almost as big as this one?
A: Not even close. Its magnitude was 6.9 and its fault area was 100 times less than this quake's, Jordan said. But it was deadly because it came so close to the city of Kobe.
"Earthquakes are like real estate," he said. What matters is "location, location, location."
(c) 2011, Los Angeles Times.
Distributed by McClatchy-Tribune Information Services.
- wong chee tat :)
Thursday, October 28, 2010
Death toll climbs to 32 in Indonesia volcano eruption
Death toll climbs to 32 in Indonesia volcano eruption
October 28, 2010 -- Updated 1214 GMT (2014 HKT)
Deadly eruptions in Indonesia
STORY HIGHLIGHTS
- Rescue and recovery efforts continue to unfold
- The volcano erupted at least three times Tuesday
- The traditional gatekeeper of Mount Merapi fell victim as well
- The gatekeeper, who was in his 80s, will be buried Thursday
Rescue and recovery efforts continue to unfold, with the Indonesian government scrambling to help tens of thousands of residents displaced by the eruption.
The volcano erupted at least three times Tuesday, forcing residents to flee.
Mount Merapi, which looms on the horizon north of the major city of Yogyakarta, is one of Indonesia's most active volcanoes and lies in one of the world's most densely populated areas. The volcano has a summit elevation of nearly 10,000 feet (3,000 meters).
Video: Volcano evacuees on edge
RELATED TOPICS
Some residents refused to flee, holding out to watch over their crops and livestock. Some residents awaited word from the traditional gatekeeper of Mount Merapi. But Maradjin, the gatekeeper, fell victim to the volcano as well.
He is to be buried Thursday. He died in his 80s, after being appointed about two decades ago by the last Sultan of Java. Maradjin's father was gatekeeper before him.
"Merapi is a house of
spirits, which also means a living mountain," Maradjin told CNN in a
2006 interview. "When Merapi emits smoke, we have to be respectful."
CNN's Kathy Quiano and Stan Grant contributed to this report.
- wong chee tat :)
Tuesday, October 26, 2010
7.7-magnitude quake hits off Indonesian island
7.7-magnitude quake hits off Indonesian island
October 25, 2010 By ALI KOTARUMALOS , Associated Press Writer
(AP) -- A powerful earthquake hit off western
Indonesia late Monday, briefly triggering a tsunami warning that sent
thousands of panicked residents fleeing to high ground. There were no
immediate reports of damage or injuries.
The 7.7-magnitude temblor struck at a depth of 13 miles (20 kilometers) off Sumatra island, said the U.S. Geological Survey.
At least five towns in the provinces of Bengkulu and West Sumatra were badly jolted, officials and witnesses said, as were the nearby Mentawai islands.
"Everyone was running out of their houses," said Sofyan Alawi, a resident in the city of Padang, adding that, with loudspeakers from mosques blaring out tsunami warnings, the roads leading to surrounding hills were quickly jammed with cars and motorcycles.
"We kept looking back to see if a wave was coming," said 28-year-old resident Ade Syahputra.
Areas closest to the epicenter of the 9:42 p.m. (10:42 a.m. EDT, 1442 GMT) quake were sparsely populated, and there were no immediate reports of damage or casualties, said Ade Edward, a disaster management agency official.
A 5.0-magnitude aftershock hit less than an hour after the original quake, and the region remained on alert for more.
Indonesia, the world's largest archipelago, is prone to earthquakes and volcanic activity due to its location on the so-called Pacific Ring of Fire.
The city of Padang was badly shaken one year ago by a 7.6-magnitude quake that killed at least 700 people and flattened or severely damaged 180,000 buildings.
That followed the 2004 tsunami off Sumatra's westernmost province of Aceh that was triggered by a 9.1-magnitude quake and killed 230,000 in a dozen countries, roughly half in Indonesia.
At least five towns in the provinces of Bengkulu and West Sumatra were badly jolted, officials and witnesses said, as were the nearby Mentawai islands.
"Everyone was running out of their houses," said Sofyan Alawi, a resident in the city of Padang, adding that, with loudspeakers from mosques blaring out tsunami warnings, the roads leading to surrounding hills were quickly jammed with cars and motorcycles.
"We kept looking back to see if a wave was coming," said 28-year-old resident Ade Syahputra.
Areas closest to the epicenter of the 9:42 p.m. (10:42 a.m. EDT, 1442 GMT) quake were sparsely populated, and there were no immediate reports of damage or casualties, said Ade Edward, a disaster management agency official.
A 5.0-magnitude aftershock hit less than an hour after the original quake, and the region remained on alert for more.
Indonesia, the world's largest archipelago, is prone to earthquakes and volcanic activity due to its location on the so-called Pacific Ring of Fire.
The city of Padang was badly shaken one year ago by a 7.6-magnitude quake that killed at least 700 people and flattened or severely damaged 180,000 buildings.
That followed the 2004 tsunami off Sumatra's westernmost province of Aceh that was triggered by a 9.1-magnitude quake and killed 230,000 in a dozen countries, roughly half in Indonesia.
©2010 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
- wong chee tat :)
Saturday, July 24, 2010
Tremors felt in Singapore from earthquake in North Sumatra
Tremors felt in Singapore from earthquake in North Sumatra
By Joanne Chan | Posted: 24 July 2010 1146 hrs
By Joanne Chan | Posted: 24 July 2010 1146 hrs
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 Singapore skyline |
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SINGAPORE: Tremors were felt in parts of Singapore Saturday morning.
Callers to the MediaCorp Hotline said the tremors, which lasted about a minute, were felt in places such as Farrer Road, Cecil Street and North Bridge Road.
Lynn Jamaludin was in her office, located on the 24th floor of Tong Eng Building on Cecil Street, when the tremors hit at around 10am.
She said: "We actually felt the desk shaking slightly, and then we felt the building was moving a bit. But it stopped after about 50 seconds. We waited for the second tremor but it didn't come so we decided to stay in the office."
The National Environment Agency's Meteorological Services Division said an earthquake of magnitude 6.25 hit northern Sumatra at 10.11am Singapore time.
The quake epicentre was some 450 kilometres from Singapore.
NEA says there is no tsunami threat to Singapore.
- CNA/jm
- wong chee tat :)
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