"This is a process that probably started eight to 10 million years ago, so you can imagine how much longer it will take until we get a classic boundary." Sumatra sits above the collision between the Indo-Australian plate and the Sunda plate. These vast segments of the Earth's rigid outer shell are converging on each other at a rate of about 5-10cm/yr. The elongated Indo-Australian, which comprises much of the Indian Ocean floor, dives under the Sunda, which carries the Indonesian island.
It is friction at their boundary - the sticking and unsticking, and the sudden release of stored energy - that is at the root of so many violent quakes, such as the magnitude 9.1 event on 26 December 2004 that set off a catastrophic tsunami.
But the 11 April 2012 tremors, although also immense in scale, did not have the same impact and generated no tsunami. This can be explained by the nature of the faulting: so-called strike-slip, where rock moves horizontally either side of the line of breakage, as opposed to vertically in tsunamigenic thrust faults.
The April tremors were also much further west, located directly on the Indo-Australian plate itself in an area of large-scale deformation and multiple faulting. It is evident that movement at the plate's ends is stressing the middle.
"Australia already moves with respect to India, and India already moves with respect to Australia. They are separated by a lot of faults. And if you look on Earth today, between plates you have only one fault. So, the process we are talking about is how we go from several faults to only one fault. That's the question - we don't know how long it takes to weaken one so that it localises all the deformation and the others stop being active. At the moment, a lot of faults in the Indian Ocean are active."
Seismic analysis indicates at least four faults were involved in the main 8.7 event, which lasted about 160 seconds. Three of the faults were parallel but offset from each other; the fourth was perpendicular to and crossed the first fault.
The 8.7 jolt "is probably the largest intraplate (within a single tectonic plate of Earth's crust) ever seismically recorded." The historic quake triggered other tremors around the world. This effect has been noted before, but the US Geological Surveyscientists were surprised by the delays involved. "For the vast majority of earthquakes, you can expect an aftershock zone not to really go beyond [1,000km]. But it's also known that very large mainshocks - like the Japanese event we had last year, the magnitude 9 event off north-east Japan - can trigger earthquakes around the world. Most of these triggered events are small and they occur instantly as the seismic waves from the large event are passing by. But this April 2012 earthquake triggered many larger and potentially damaging earthquakes around the world, and with a time delay of hours or up to several days. That EFFECTIVELY EXTENDED THE AFTERSHOCK ZONE TO THE ENTIRE GLOBE." (map)
but great actions speak to all mankind.**
Theodore Roosevelt
LARGEST QUAKES -
Live Seismograms - Worldwide (update every 30 minutes)
This morning -
None 5.0 or higher.
Yesterday -
9/26/12 -
6.9 ANDREANOF ISLANDS, ALEUTIAN IS.
5.2 ANTOFAGASTA, CHILE
5.2 SOUTH OF FIJI ISLANDS
5.3 TONGA
5.2 SOUTH OF KERMADEC ISLANDS
5.2 TONGA
9/25/12 -
6.3 GULF OF CALIFORNIA
5.1 SOLOMON ISLANDS
5.3 TONGA
5.1 UNIMAK ISLAND REGION, ALASKA
5.0 OFF EAST COAST OF HONSHU, JAPAN
5.1 HINDU KUSH REGION, AFGHANISTAN
5.3 SOUTH OF FIJI ISLANDS
5.7 TONGA
5.3 SOUTH OF AFRICA
9/24/12 -
5.5 TONGA
5.2 MINDANAO, PHILIPPINES
VOLCANOES -
Volcano Webcams
Increase of eruptive activity at Mexico’s Popocatepetl Volcano - At least 26 eruptions accompanied by steam and gas, as well as a volcano tectonic quake were registered as a consequence of the Mexican volcano Popocatepetl activity, it was reported Tuesday. The eruptions were of low and medium intensity with no ash expulsion in any of them. The volcano tectonic quake was registered at 11.54 local time (16:54 GMT). The alert light of volcano activity remains yellow phase 2. The Popo is located at the center of the country, in the territorial limits of the Morelos, Puebla and Mexico states.
Marapi Volcano erupts with smoke on Sumatra - Mount Marapi volcano erupted on Wednesday on Indonesia's Sumatra island, spewing thick grey smoke up to 1.5 kilometres into the sky. The eruption is its strongest since August last year when its alert level was raised.
TROPICAL STORMS -
In the Atlantic - - Tropical storm Nadine was located about 640 mi [1030 km] SSW of the Azores. No threat to land.
In the East Pacific -
- Tropical storm Miriam was located about 385 mi [615 km] WSW of the southern tip of Baja California. Swells generated by Miriam will continue to affect the south and west coasts of the southern and central Baja Peninsula today but will begin to gradually subside on Friday.
In the Western Pacific -
- Super Typhoon Jelawat was located approximately 430 nm south-southwest of Kadena Air Base, Okinawa, Japan. Expected to make landfall in Honshu, Japan. All models now track across Japan and into the Sea of Japan, but historically storms are not able to cross Japan's mountainous geography.
- Tropical storm Ewiniar - was located approximately 345 nm south-southeast of Yokosuka, Japan. No threat to land.
Nadine is back - The storm that won't die: Nadine regenerates into tropical storm. Tropical Storm Nadine is back, like a nasty cold you just can't get rid of. Nadine had moved southeastwards over cool waters on Friday and Saturday, which robbed the storm of its heavy thunderstorms and tropical characteristics. But the stubborn weather system regenerated into a tropical storm in the far eastern Atlantic Ocean nearly two weeks after becoming a tropical storm in the central Atlantic back on September 11th.
Tropical Storm Miriam is fast weakening off Mexico's Baja California peninsula. Miriam had top sustained winds of 45 mph (72 kph) at 11 p.m. EDT Wednesday, down sharply.
NASA satellite images of Super Typhoon Jelawat and Tropical Storm Ewiniar.
SEVERE RAIN STORMS, FLOODING, LANDSLIDES -
UK floods: Homes at risk as misery continues. - Flooding misery is continuing as rising waters put thousands of people's homes at risk around the UK. The wet weather is still causing chaos in many communities, with roads, rail and buildings affected. A block of flats in Newburn, Newcastle, is said to be close to collapse and Tadcaster, North Yorkshire, was split in two after a bridge was closed. Homes and businesses in York city centre were also flooded after the River Ouse burst its banks.
Local people said the flooding could be the most severe in recent memory, however the Environment Agency said the river would not breach the city's flood defences. There are still nearly 60 flood warnings - indicating flooding is expected - and more than 100 flood alerts - meaning flooding is possible - in England and Wales, and three flood alerts in Scotland. In Wiltshire, an 11-year-old boy is in a "potentially life-threatening condition" after being struck by lightning. While in Newcastle, police branded looters "despicable" after a bicycle shop in a flood-hit community was raided while roads were blocked by water and silt.
A man has spoken of his escape from his car seconds before it was submerged by raging floodwater in Newburn, Newcastle. Aa small bridge partially collapsed in the village of Scorton, near Richmond. Train services remain subject to some disruption and delays in northern England and Wales. The North Sea foam that swept into Aberdeen during storms on Tuesday has cleared. London Road in Northwich town centre is closed amid fears the River Weaver will burst its banks. North Yorkshire firefighters evacuated about 20 homes in Dalton, near Thirsk.
The Newburn flats' foundations were badly damaged after heavy rain deluged the area. The flats have been evacuated. The Spencer Court flats are "extremely unstable" and they were waiting for a break in the weather so the damage could be assessed. "I have never seen anything like this in 33 years of civil engineering experience." Flooding is still causing problems for roads, rail and buildings, as THE MOST INTENSE SEPTEMBER STORM FOR 30 YEARS continues. The heaviest rush-hour showers were seen in south-west England, circulating around low pressure over Torbay. There are reports of nearly 20mm (0.75ins) of rain falling over the course of an hour in some areas.
The worst of the rainfall is over but the worry is that it was still running into river systems so there could be more flooding. Morpeth in Northumberland suffered flooding in 2008 and again during this storm but defences are not expected to start being built until next year. Residents are afraid every time it rains: "There's always panic in the town, we always check the weather. When you've been flooded, you always worry about when it rains. Four years is a long time. At least we might be able to rest easily at night when it's raining." "It's really tragic for this community because they actually have a flood scheme that is about to start which would protect a lot of homes in Morpeth."
Tuesday saw some places deluged in what was THEIR WETTEST SEPTEMBER DAY ON RECORD, with hundreds of homes being evacuated. Hundreds of people spent the night in temporary shelter and parts of many roads were closed. More than 300 properties have flooded across the country since the storm began on Sunday, including in Morpeth, Durham, Chester-le-Street and Stockton. (photos & video)
EXTREME HEAT & DROUGHT / CLIMATE CHANGE -
Ecuador - Forest fires devastating Ecuador have left five people dead and 73 injured, consuming more than 17,600 hectares of woodland and crops. The five deaths, including one of the firefighters, occurred in the provinces of Azuay, Bolivar, Chimborazo, Cotopaxi and Tungurahua, while most of the 73 injured were in Chimborazo and Pichincha. In all there have been 3069 forest fires since June 1, when a period of drought set in. The fires have wiped out 17,484 ha of woods and scrubland high in the Andes as well as 142 ha of crops, while another 31 ha of crops were affected but not completely destroyed. The province with the most blazes is Pichincha in the Andes region.
HEALTH THREATS -
New coronavirus linked to two severe illnesses - Reports of a novel coronavirus linked to two severe illnesses with Saudi Arabian connections put the public health world on alert and conjured up memories of SARS (severe acute respiratory syndrome), a coronavirus infection that killed close to 800 people in 2002 and 2003.
Peanut butter recalled after multistate Salmonella outbreak - Salmonella outbreak linked to peanut butter grows to 30 cases. A person in Nevada infected with Salmonella Bredeney who developed symptoms Sep 11 has increased the case count in the multistate outbreak linked to contaminated peanut butter to 30. The number of affected states also increased by 1, to 19. Hospitalizations remained at 4, with no deaths, and dates of illness onset range from Jun 11 to Sep 11. Sunland Inc. of Portales, N.M., recalled multiple peanut and almond butter products because of possible Salmonella contamination. Sunland supplied Trader Joe's with the Creamy Salted Valencia Peanut Butter that the CDC linked to the outbreak. Illnesses that occurred after August 30, 2012 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. List of recalled nut products (pdf file)
Cholera outbreak in Sierra Leone tops 19,000 cases - The cholera outbreak in Sierra Leone that started in February has now topped 19,000 cases and has caused 274 deaths. The outbreak is UNUSUAL in that it began during the country's dry season. When the outbreak peaked in August during the rainy season, more than 2,000 cases were being reported per week. The WHO said having a cholera command center, detecting cases early, and disseminating safety messages have been crucial to outbreak-control efforts. The report also said poor sanitation in the country and low supplies of key treatments such as oral rehydration solution remain as top challenges.
RECALLS & ALERTS
