ringg of fire






updated September 4, 2012 

PAGE 197



Indonesia quake a record, risks for Aceh grow

Reuters) - The powerful undersea earthquake off the Indonesian island of Sumatra this week was a once in 2,000 years event, and although it resulted in only a few deaths, it increases the risks of a killer quake in the region, a leading seismologist said.

Wednesday's 8.6 magnitude quake and a powerful aftershock were "strike-slip" quakes and the largest of that type recorded, Kerry Sieh, director of the Earth Observatory of Singapore, told Reuters.

"It's a really an exceptionally large and rare event," he said.

"Besides it being the biggest strike-slip earthquake ever recorded, the aftershock is the second biggest as far as we can tell," said Sieh, who has studied the seismically active, and deadly, fault zones around Sumatra for years.

Strike-slip quakes involve the horizontal movement of colliding earth plates, and are typically less powerful than those where there is vertical movement. They are also less likely to trigger big tsunamis, or tidal waves.

A magnitude 9.1 quake in roughly the same region on Boxing Day in 2004 decimated Aceh province on Sumatra and killed over 230,000 people in 13 countries around the Indian Ocean.

Sumatra, the westernmost island in the sprawling Indonesian archipelago, has a history of powerful quakes and tsunamis, most triggered by an offshore zone along its entire length, where the Indian-Australian tectonic plate is forced under the Eurasian plate.

This creates a deep ocean trench as one plate slides under the other at a rate of several centimeters a year. In this zone, called the Sunda megathrust, stress builds up when the subducting Indian-Australian plate bends the Eurasian plate like a spring board as it moves down into the Earth's crust.

Eventually enough stress builds up that the edge of Eurasian plate suddenly jolts upward, triggering an earthquake. The sudden uplift of the seafloor and huge pulse of seawater triggers a tsunami.

Over the centuries, repeated magnitude 8 and 9 quakes have struck along portions of the megathrust zone off the coast of Sumatra, flattening towns and killing thousands of people.


Wednesday's event was different, Sieh said, because it occurred further west from the megathrust zone in a fault that runs north-south. This strike-slip fault involved a sudden horizontal movement of the Indian and Australian plates along hundreds of kilometers, preliminary data suggest.

Sieh said the Indian plate and Australian plate are moving relative to each other horizontally at about 1 cm a year.

"If all of that ... is taken up on this one fault and if you make some crude calculations about how much slip occurred during this earthquake, say 20 meters. It means that this earthquake shouldn't happen more than once every 2,000 years."

Wednesday's quake caused few casualties and triggered very small waves, despite its magnitude. But the sting in the tale is that it likely to have increased stress on the plate boundaries near Aceh, increasing the risks of another major earthquake in the same area as the 2004 disaster.

In addition, research by Sieh and colleagues published in 2010 showed that the 2004 Aceh quake only relieved about half the stress that has built up over the centuries along a 400 km portion of the megathrust faultline.

That makes another major quake in the area a matter of time.

Adding to concerns, further south along another 700 km portion of the megathrust fault under the Mentawai islands, Sieh and colleagues in a separate 2008 research said so much stress was building up on this section that one or more major quakes were likely within years.

The Mentawai islands, a popular surfing destination, are a chain of about 70 islands off the western coast of Sumatra. They face the city of Padang on Sumatra, home to about one million people and likely to be in the path of any tsunami that is triggered.

"I am very confident that we are very likely to have within the next few decades to have this great Mentawai earthquake that will have a magnitude at least as big as yesterday's," said Sieh.

And when it does, history shows there will be more than one quake within a few years.

He said a magnitude 8.4 quake in 2007 that struck this part of the megathrust relieved only a small portion of the pent-up pressure. The last time it ruptured was a magnitude 9 quake in 1833 and an 8.4 quake in 1797.

"We've had so many big earthquakes around in Sumatra in the past few years that it seems like an awful lot of the faults around there seem ready to go."

(Editing by Sanjeev Miglani and Raju Gopalakrishnan)


Five dead and seven hurt after Sumatran earthquake

Agence France-PresseApril 13, 2012




Farmers harvest rice near an area where the wall of the Banda Aceh prison collapsed one day after an earthquake.

Photograph by: Getty Images , Agence France-Presse

Five people died and at least seven were injured as massive earthquakes struck off Indonesia's Sumatra island, officials said Thursday.

Officials said they believed at least two people died of heart attacks and three others died of shock in the quakes on Wednesday.

"Based on data collected on victims and damage, five people died, one person is critically injured and six others had minor injuries," National Mitigation Agency spokesman Sutopo Purwo Nugroho said.

An 8.6-magnitude quake struck 431 kilometres off the city of Banda Aceh late afternoon Wednesday, and was followed by another undersea quake measured at 8.2, with aftershocks continuing through the night.

All of the casualties were in Aceh province, Nugroho said, with the critically injured victim a child who fell from a tree.

Communities in Aceh have now returned to daily life, Nugroho added, in stark contrast to the devastation caused by the massive 2004 Indian Ocean tsunami which killed 170,000 people in the province alone and wiped out entire towns.

Minimal damage was caused this time round because government regulations ensured buildings have better resistance to quakes, according to the United Nations Development Programme (UNDP), and people were better prepared.

"The buildings in Aceh are now stronger because the government has set certain standards that oblige contractors to ensure antiearthquake aspects are put in place," UNDP national project coordinator for Aceh Fahmi Yunus said.

Experts said an Indian Ocean-wide warning system - that alerts people of a potential tsunami, through SMS messages, smartphones and social media - helped spread the word across Indonesian Sumatra and other nations such as Thailand and India, prompting people to seek higher ground.

After the first quake struck, people grabbed their families and poured into the streets in search of safe havens and higher areas, having gone through repeated disaster drills since the 2004 quake and tsunami.

Police tried to manage throngs of residents fleeing coastal areas in cars and on motorbikes, while panicked teachers tried to evacuate children from schools.

Damage was minimal also because the epicentre was much farther offshore than 2004, according to the Meteorology and Geophysics Agency, and did not generate a massive tsunami, which was responsible for most of the damage eight years ago.

Syamsul Maarif, head of the National Disaster Agency (BNPB), told reporters that losses from the latest quake were estimated at only 2 billion rupiah ($218,000).

Indonesia calculates losses from the 2004 disaster at 39 trillion rupiah ($4.3 billion).

© Copyright (c) The StarPhoenix



Preliminary Earthquake Report
Magnitude 8.2 Mw
  • 11 Apr 2012 10:43:09 UTC
  • 11 Apr 2012 16:43:09 near epicenter
  • 11 Apr 2012 02:43:09 standard time in your timezone
Location 0.773N 92.452E
Depth 16 km
  • 615 km (382 miles) SSW (211 degrees) of Banda Aceh, Sumatra, Indonesia
  • 1061 km (659 miles) WSW (256 degrees) of KUALA LUMPUR, Malaysia
Location Uncertainty Horizontal: 14.2 km; Vertical 6.4 km
Parameters Nph = 101; Dmin = 573.3 km; Rmss = 0.95 seconds; Gp = 39°
M-type = Mw; Version = 7
Event ID US c00090da

For updates, maps, and technical information, see:
Event Page
USGS Earthquake Hazards Program





National Earthquake Information Center
U.S. Geological Survey

April 12, 2012

NEWS ALERT: Ring of Fire Cont's -

Massive Subduction Zones at Risk

by Mitch Battros - Earth Changes Media

Early Thursday morning a 6.9 magnitude quake hit in the Gulf of California. (see EQ list below) This is no doubt in relation to the series of quakes along the ring-of-fire which begun in the Indian Ocean near Sumatra with an 8.6 quake on April 11th.

Gulf of California EQ List: http://on.doi.gov/b46jEQ


Later that day, some fourteen hours later, the rift found its way to the US Northwest off the coast of Oregon. Then fourteen "minutes" later, Mexico was hit with a 7.0 near Michoacan. The rift continues hitting the Gulf of Calif. with a 6.9 mag. quake seventeen hours after Mexico.



Anscary dream of california earthquake 


other point of interest - is rare quake events which have occurred in Utah and Oklahoma. Regarding Utah; there are some seismologists who believe there is a connection between the Cascadia Subduction Zone - Utah and Yellowstone Caldera. As for Oklahoma, some believe the cause may be related to man-made drilling leaving this area vulnerable to deep mantle movement. Utah and Southern Calif. EQ




Earthquake Lists & Maps

United States World
Deadly Earthquakes
Earthquake Density Maps
Earthquake Information
Earthquake Statistics
  • United States
    Number of earthquakes per year, listed by magnitude range, 2000 to present
  • World
    Number of earthquakes per year, listed by magnitude range, 2000 to present
Historic Earthquakes
  • United States List
    Selected earthquakes of general historic interest.
    Since 1700, by date, State, or magnitude, with links to event summary pages
Largest Earthquakes
Last Earthquake
Seismicity Maps
Significant Earthquakes


eqarthquake database on this site 

Earthquake Hazards Map Study Finds Deadly Flaws, MU Researcher Suggests Improvements

map Samoa 2009
by Staff Writers
Columbia MO (SPX) Sep 04, 2012

File image.

Three of the largest and deadliest earthquakes in recent history occurred where earthquake hazard maps didn't predict massive quakes. A University of Missouri scientist and his colleagues recently studied the reasons for the maps' failure to forecast these quakes. They also explored ways to improve the maps. Developing better hazard maps and alerting people to their limitations could potentially save lives and money in areas such as the New Madrid, Missouri fault zone.

"Forecasting earthquakes involves many uncertainties, so we should inform the public of these uncertainties," said Mian Liu, of MU's department of geological sciences.

"The public is accustomed to the uncertainties of weather forecasting, but foreseeing where and when earthquakes may strike is far more difficult. Too much reliance on earthquake hazard maps can have serious consequences. Two suggestions may improve this situation.

"First, we recommend a better communication of the uncertainties, which would allow citizens to make more informed decisions about how to best use their resources. Second, seismic hazard maps must be empirically tested to find out how reliable they are and thus improve them."

Liu and his colleagues suggest testing maps against what is called a null hypothesis, the possibility that the likelihood of an earthquake in a given area - like Japan - is uniform. Testing would show which mapping approaches were better at forecasting earthquakes and subsequently improve the maps.

Liu and his colleagues at Northwestern University and the University of Tokyo detailed how hazard maps had failed in three major quakes that struck within a decade of each other. The researchers interpreted the shortcomings of hazard maps as the result of bad assumptions, bad data, bad physics and bad luck.

Wenchuan, China - In 2008, a quake struck China's Sichuan Province and cost more than 69,000 lives. Locals blamed the government and contractors for not making buildings in the area earthquake-proof, according to Liu, who says that hazard maps bear some of the blame as well since the maps, based on bad assumptions, had designated the zone as an area of relatively low earthquake hazard.

Leogane, Haiti - The 2010 earthquake that devastated Port-au-Prince and killed an estimated 316,000 people occurred along a fault that had not caused a major quake in hundreds of years. Using only the short history of earthquakes since seismometers were invented approximately one hundred years ago yielded hazard maps that were didn't indicate the danger there.

Tohoku, Japan - Scientists previously thought the faults off the northeast coast of Japan weren't capable of causing massive quakes and thus giant tsunamis like the one that destroyed the Fukushima nuclear reactor.

This bad understanding of particular faults' capabilities led to a lack of adequate preparation. The area had been prepared for smaller quakes and the resulting tsunamis, but the Tohoku quake overwhelmed the defenses.

"If we limit our attention to the earthquake records in the past, we will be unprepared for the future," Liu said.

"Hazard maps tend to underestimate the likelihood of quakes in areas where they haven't occurred previously. In most places, including the central and eastern U.S., seismologists don't have a long enough record of earthquake history to make predictions based on historical patterns.

"Although bad luck can mean that quakes occur in places with a genuinely low probability, what we see are too many 'black swans,' or too many exceptions to the presumed patterns."

"We're playing a complicated game against nature," said the study's first author, Seth Stein of Northwestern University.

"It's a very high stakes game. We don't really understand all the rules very well. As a result, our ability to assess earthquake hazards often isn't very good, and the policies that we make to mitigate earthquake hazards sometimes aren't well thought out. For example, the billions of dollars the Japanese spent on tsunami defenses were largely wasted.

"We need to very carefully try to formulate the best strategies we can, given the limits of our knowledge," Stein said. "Understanding the uncertainties in earthquake hazard maps, testing them, and improving them is important if we want to do better than we've done so far."

The study, "Why earthquake hazard maps often fail and what to do about it," was published by the journal Tectonophysics. First author of the study was Seth Stein of Northwestern University. Robert Geller of the University of Tokyo was co-author. Mian Liu is William H. Byler Distinguished Chair in Geological Sciences in the College of Arts and Science at the University of Missouri.

Click here to watch a five 5-minute video summary presented at the 2012 UNAVCO science workshop "Bad assumptions or bad luck: Tohoku's embarrassing lessons for earthquake hazard mapping".

Related Links
Geological Sciences at University of Missouri
Bringing Order To A World Of Disasters
When the Earth Quakes
A world of storm and tempest


Web Results



    The greatest number of earthquake-related deaths this year has been in India, where as many as 30000 people may have been killed due to the 7.7, January 26 ...


    www.greatdreams.com/earthquake-survival.htm - Similarto EARTHQUAKE SURVIVAL


  • Morocco Earthquake

    www.greatdreams.com/morocco-earthquake.htm - Similarto Morocco Earthquake

    Feb 25, 2004 ... Survivors of the earthquake that has killed nearly 600 people in northern Morocco have blocked a main road, in a protest against the lack of ...







Note: A point of interest is there was a "foreshock" of 6.2 nine hours prior to the larger 6.9. This is an event I look for when assessing mega-quakes which could occur at subduction zones.




this blog continues on page 198