Damage from the March 11 earthquake was extensive in part simply because it was so large. But the two-faced rupture made the devastation greater than it might have been otherwise. "Now that this has been observed in the Tohoku-Oki earthquake, what we need to figure out is whether similar earthquakes - and large tsunamis - could happen in other subduction zones around the world."
The earthquake occurred in a known subduction zone, where one great tectonic plate is being forced down under another tectonic plate and into the Earth's interior along an active fault. But no one predicted its ferocity. The earthquake was THE LARGEST QUAKE EVER RECORDED IN JAPAN, and tied for fourth largest in the world since 1900. The 30-foot tsunami washed over sea walls and swept inland for miles. The deeper part of the quake's fault plane, which sloped downward to the west, was bound by dense, hard rock on each side. This rock transmitted the seismic waves very efficiently, maximizing the shaking.
The shallower part of the fault surface, which sloped upward to the east and surfaced at the Japan Trench - where the overlying plate is warped downward by the motion of the descending plate - had massive slip.
This punched the ocean water upward with great ferocity. To make matters worse, the rupture occurred in deep ocean, so a large volume of water was displaced. "It exploded into tremendously large slip. It displaced the seafloor dramatically. This amplification of slip near the surface was predicted in computer simulations of earthquake rupture, but this is the first time we have clearly seen it occur in a real earthquake."
You make it heaven or you make it hell by your actions.**
George Harrison
LARGEST QUAKES -
This morning -
5.3 TONGA REGION
Yesterday -
5/25/11 -
5.2 OFF EAST COAST OF HONSHU, JAPAN
5.1 SEA OF OKHOTSK
5.0 PANAMA
29 aftershocks in Turkey ranging from 2.4 to 3.6
Japan Earthquake Appears to Increase Quake Risk Elsewhere in the Country - Japan's recent magnitude 9.0 earthquake, which triggered a devastating tsunami, relieved stress along part of the quake fault but also has contributed to the build up of stress in other areas, putting some of the country AT RISK FOR YEARS of sizeable aftershocks and perhaps new main shocks. After studying data from Japan's extensive seismic network, researchers have identified several areas at risk from the quake, Japan's largest ever, which already has triggered a large number of aftershocks.
Data from the magnitude 9.0 Tohoku earthquake on March 11 has brought scientists a small but perceptible step closer to a better assessment of future seismic risk in specific regions. "Research over the past two decades has shown that earthquakes interact in ways never before imagined. A major shock does relieve stress - and thus the likelihood of a second major tremor - but only in some areas. The probability of a succeeding earthquake adjacent to the section of the fault that ruptured or on a nearby but different fault can jump" significantly.
The Tohoku earthquake, centered off northern Honshu Island, provided an "unprecedented" opportunity to utilize Japan's "superb monitoring networks" to gather data on the quake. The Tohoku quake, the fourth largest earthquake ever recorded, was "the best-recorded [large quake] the world has ever known." This made the quake a "special" one in terms of scientific investigation. "We felt we might be able to find something we didn't see before" in previous quakes.
The magnitude 9 quake appears to have influenced large portions of Honshu Island. At particular risk are the Tokyo area, Mount Fuji and central Honshu including Nagano. The Kantu fragment, which is close to Tokyo, also experienced an increase in stress. Previous government estimates have put Tokyo at a 70 percent risk for a magnitude 7 earthquake over the next 30 years. The new data from the Tohoku quake increase those odds to "more than 70 percent. That is really high."
"There remains a lot of real estate in Japan - shore and off - that could host large, late aftershocks of the Tohoku quake. In addition to the megathrust surface to the north or south of the March 11 rupture, we calculate that several fault systems closer to Tokyo have been brought closer to failure, and some of these have lit up in small earthquakes since March 11. So, in our judgment, Central Japan, and Tokyo in particular, is headed for a long vigil that will not end anytime soon." Aftershocks, as well as new mainshocks, could continue for "weeks, months, years." The magnitude of future quakes is proportional to the length of the fault involved.
Researchers report "a broad and UNPRECEDENTED increase in seismicity rate for microearthquakes over a broad (360 by 120 mile) area across inland Japan, parts of the Japan Sea and the Izu islands, following the 9.0 Tohoku mainshock. The crust on the land was turned on…far away from a fault." Most of these are relatively small quakes - magnitude 2 to 4 - "but a lot of them. This is surprising; WE'VE NEVER SEEN THIS BEFORE. Such small events may have happened following major quakes in other places but may have been missed due to poor seismic networks. The 9.0 Tohoku quake caught many people including scientists by surprise. It had been thought that a large quake in this area would go up to about 8.2, not 9.0." That estimate was significantly influenced by historical data. "The Tohoku quake reminded us that considering only the historical earthquakes is inadequate, even in a country of relatively long written records like Japan and China. Historical records, and especially the instrumental records, are indeed too short to provide a full picture of the potential of large earthquakes in a region. Thus we must encourage many more studies to find geological evidence (for example, through analyzing sediment cores extracted on land and undersea) that might provide clues of large earthquake and tsunami events that occurred hundreds to thousands of years ago. We must recognize that because our knowledge is incomplete, our estimation of seismic hazard is likely to be underestimated in many cases. Thus we must prepare for POTENTIAL HAZARD THAT MIGHT BE WORSE THAN WE ALREADY KNOW." The finding that a quake such as this one can increase stresses elsewhere "means that new quakes could occur in the region. We must factor in this new information on stresses into earthquake preparedness."
HAITI - Haiti's prime minister-designate says the international commission overseeing post-earthquake rebuilding is faulty and must be replaced.
The Haiti Earthquake occurred in a complex, active seismic region. - The magnitude 7.0 earthquake that triggered disastrous destruction and huge death tolls in Haiti occurred in a highly complex tangle of tectonic faults.
VOLCANOES -
Iceland's Grimsvotn volcano eruption is said to be in its final stages with airlines beginning to get back to normal schedules. A meteorologist at the Icelandic met office said there were indications that the eruption was ceasing.
TROPICAL STORMS -
TYPHOON 04W (SONGDA) was LOCATED APPROXIMATELY 330 NM EAST OF MANILA, PHILIPPINES.
Typhoon 'Chedeng' will gain more strength.. - Typhoon Chedeng (international name: Songda) will become stronger as it nears the Philippines, U.S. military weather forecasters warned on Wednesday.
The typhoon is already packing maximum sustained winds of 150 kilometers near the center and gustiness of up to 185 kph, according to weather bureau PAGASA, in its 11 p.m. tropical cyclone update. Chedeng has intensified over the past 12 hours in the highly favorable environment of the Philippine Sea. The typhoon will only weaken after skirting the Philippines's eastern section and upon reaching the waters north of Okinawa, Japan.
While PAGASA predicts Chedeng to make landfall over the Aurora-Isabela area on Friday afternoon, the JWTC believes that the typhoon will miss Luzon and stay at sea. PAGASA said that based on their data, Chedeng is estimated to have rainfall of between 32-64 millimeters per hour. Compared to tropical storm Ondoy (Ketsana) in 2009, Chedeng is "stronger" since the rainfall brought by Ondoy - averaging 56 mm/h - was due to the storm and an intertropical convergence zone, while Chedeng's rainfall is solely due to the typhoon. The storm is moving northwest at 15 kph and is expected to be 190 km east of Baler, Aurora province on Thursday night.
"Residents in low lying and mountainous areas under signals #2 and #1 are alerted against possible flashfloods and landslides. Likewise, those living in coastal areas are alerted against big waves or storm surges generated by this tropical cyclone." The typhoon is also expected to enhance the southwest monsoon and bring rains over Visayas and Mindanao.
SEVERE RAIN STORMS, FLOODING, LANDSLIDES -
U.S. - Forecasters urge residents to take cover as storms rip through region. Tornado warnings issued for wide swath of Tennessee, including Memphis and Nashville. Forecasters warned thousands to take cover as severe storms pummeled parts of Arkansas and Tennessee early today, while communities in neighboring states picked up the pieces after tornadoes cut a path of destruction a day earlier. A line of strong thunderstorms stretches from northern Indiana all the way to Mississippi.
At least 16 people have died in the latest round of storms that struck Oklahoma, Arkansas and Kansas late Tuesday and early Wednesday. Ten people were killed in Oklahoma, four in Arkansas and two in Kansas.
The National Weather Service warned residents from Memphis to Nashville to take shelter and, in some cases, evacuate, after spotters reported a possible tornado moving toward eastern Tennessee communities. Huge swathes of the region face a "particularly dangerous situation," including destructive tornadoes, golf-ball sized hail and wind gusts up to 70 miles per hour.
The most severe damage appeared to be in central Oklahoma's Canadian County, which includes a sliver of Oklahoma City. At least seven people were killed and more than 100 were wounded. Search and rescue teams worked into the night Wednesday, searching for a 3-year-old who disappeared during the storms in Canadian County. He was with his pregnant mother and his siblings in their home when the storm hit. The family had taken refuge in a bathtub when the storm barreled through, killing a 15-month-old and injuring the mother and a 5-year-old. The mother was listed in stable condition. "They did get the heartbeat of the baby yesterday, so the baby's stable." The father was out of town Tuesday when the storms struck. He has since returned and is searching for the 3-year-old. "Last I heard, they're searching a 16-mile stretch." It's been a historic tornado season in the U.S. More than 500 people have been killed. That makes 2011 the deadliest season since 1953, when 519 people were killed in twisters.
Oklahoma's Governor declared a state of emergency Wednesday in 68 Oklahoma counties hit by the tornadoes and other severe weather. Only nine counties in the state were not included in the declaration. Twisters also brewed in Dallas and several northern Texas counties. In Dallas, a man died Wednesday after being electrocuted by power line that appear to have been downed during the storm. The storms also disrupted air traffic, forcing the cancellation of more than 140 flights at Dallas- Fort Worth International Airport because of hailstorms that moved through early Wednesday. About 10,000 were stranded at the airport overnight.
Montana Floods Kill One, Leave One Missing - More Extreme Weather to Come. Montana is the latest to get extreme floods and they are now moving on towards neighboring states such as Wyoming and Utah. “Flooding that besieged rural Montana communities claimed at least one life and left another person missing as authorities in at least two more Western states braced for high water and heavy rain in the coming days." Montana's governor declared a statewide emergency Monday as broad areas of the state’s southeastern counties remained underwater. A number of rural communities in eastern Montana, including those on the Crow Reservation, were hardest hit. The water has destroyed infrastructure, covered major roads, and inundated town centers. More rain could be coming in the next week, adding to the flooding. Utah is now getting heavy rains and, of course, melting snow. Wyoming is also expecting high water and flooding in coming days due to recent storms.
