7.6 Costa Rican earthquake did not relieve fault pressure: expect another one equal or greater, scientists warn
September 12, 2012 – COSTA RICA - After a series of analyses conducted in the northwestern province of Guanacaste, experts from the Volcanological and Seismological Observatory of Costa Rica (Ovsicori) reported Tuesday that another quake of equal or greater magnitude could occur in Nicoya Peninsula, but predicting when it would happen is “impossible.” Marino Protti, Ovsicori’s lead scientist, explained that the magintude-7.6 earthquake on Sept. 5 caused a 40 percent slip and an inclination of 1.8 meters on the fault located in Nicoya. He also said that although the quake was the “big one” experts had been expecting for Guanacaste, the fault ruptured by only 50 percent, meaning that the possibility that another earthquake of equal or greater magnitude in the area still remains. Ovsicori’s report, released Tuesday, also stated that the earthquake triggered the activation of three faults in Aguas Zarcas (in the northern region), the Guanacaste Volcanic Area and Irazú Volcano (north of Cartago). Seismologists will continue monitoring the areas. By Tuesday morning, the total count of aftershocks from the recent earthquake was 1,650. On Sept. 5 at 8:42 a.m., the 7.6-magnitude earthquake shook the country and was felt as far away as Nicaraguan and Panama. Its epicenter was located 20 kilometers northwest of Sámara in the Nicoya Península.
Activity increases at Indonesia’s Mount Anak Krakatau volcano
September 11, 2012 – INDONESIA – Activity at one of Indonesia’s most dreaded volcanoes continues to increase. Ongoing activity by Indonesia’s Mount Anak Krakatau has residents of nearby coastal areas concerned as the volcano spewed more lava, officials said. On Monday the volcano in the Sunda Strait spewed hot lava and other volcanic material 2,000 feet above its peak, the Antara news agency reported. “Tremors have not stopped rocking this area since yesterday,” Hamdani, the head of the volcano monitoring post in the village of Hargopancuran, South Lampung, said. Black clouds were obscuring the peak of the volcano, Hamdani said. Officials warned fishermen to stay away from the volcano although they said the ongoing tremors would not cause a tsunami. “But it is difficult to predict Anak Krakatau,” Hamdani said. Krakatau’s explosion in the 18th century, so loud it was heard 1,000 miles away, caused one of history’s most devastating tsunamis.
Costa Rica’s earthquake aftermath: 1650 aftershocks and still shaking
September 11, 2012 – COSTA RICA – The latest report from the Volcanological and Seismological Observatory of Costa Rica (Ovsicori), released Monday morning, states that 1,650 aftershocks have been registered since the magnitude- 7.6 earthquake that hit the country last Wednesday. The strongest aftershock was felt Saturday, with a magnitude of 5.6. However, it was felt only in the Central Valley. Ovsicori seismologist Walter Jiménez said the aftershocks will continue in upcoming days, but he also stated that the magnitudes and frequencies of them will go down, ranging from 2 to 3 in magnitude.
Giant ‘balloon of magma’ inflates under Greece’s Santorini volcano
September 10, 2012 – GREECE – A new survey suggests that the chamber of molten rock beneath Santorini’s volcano expanded 10-20 million cubic meters – up to 15 times the size of London’s Olympic Stadium – between January 2011 and April 2012. The growth of this ‘balloon’ of magma has seen the surface of the island rise 8-14 centimetres during this period, a team led by Oxford University scientists has found. The results come from an expedition, funded by the UK’s Natural Environment Research Council, which used satellite radar images and Global Positioning System receivers (GPS) that can detect movements of the Earth’s surface of just a few millimetres. The findings are helping scientists to understand more about the inner workings of the volcano which had its last major explosive eruption 3,600 years ago, burying the islands of Santorini under metres of pumice. However, it still does not provide an answer to the biggest question of all: ‘when will the volcano next erupt?’ A report of the research appears in this week’s Nature Geoscience. In January 2011, a series of small earthquakes began beneath the islands of Santorini. Most were so small they could only be detected with sensitive seismometers but it was the first sign of activity beneath the volcano to be detected for 25 years. Dr. Juliet Biggs of Bristol University, also an author of the paper, said: ‘People were obviously aware that something was happening to the volcano, but it wasn’t until we saw the changes in the GPS, and the uplift on the radar images that we really knew that molten rock was being injected at such a shallow level beneath the volcano. Many volcanologists study the rocks produced by old eruptions to understand what happened in the past, so it’s exciting to use cutting-edge satellite technology to link that to what’s going on in the volcanic plumbing system right now.’ Professor David Pyle of Oxford University’s Department of Earth Sciences, an author of the paper, said: ‘For me, the challenge of this project is to understand how the information on how the volcano is behaving right now can be squared with what we thought we knew about the volcano, based on the studies of both recent and ancient eruptions. There are very few volcanoes where we have such detailed information about their past history.’ The team calculated that the amount of molten rock that has arrived beneath Santorini in the past year is the equivalent of about 10-20 years growth of the volcano. But this does not mean that an eruption is about to happen: in fact the rate of earthquake activity has dropped off in the past few months.
Researchers believe huge underwater volcanic eruptions were part of last extinction period
September 10, 2012 – GEOLOGY – Popular opinion holds that an asteroid struck the Earth 65 million years ago, hustling out the Age of Dinosaurs and allowing the mammals – us – to rise. But new research now paints another picture – with the University of Washington indicating that a separate extinction came shortly first, triggered by volcanic eruptions that warmed the planet and killed life on the ocean floor. They suggest that by the time of the asteroid impact, life on the seafloor – mostly species of clams and snails – was already perishing, because of the effects of huge volcanic eruptions on the Deccan Plateau, in what is now India. The well-known dinosaur extinction event is believed to have been triggered by an asteroid at least six miles in diameter slamming into Mexico’s Yucatán Peninsula. Thomas Tobin, a UW doctoral student in Earth and space sciences, said: ‘The eruptions started 300,000 to 200,000 years before the impact, and they may have lasted 100,000 years.’ During the earlier extinction it was primarily life on the ocean floor that died, in contrast to the later extinction triggered by the asteroid impact, which appeared to kill many more free-swimming species. The eruptions would have filled the atmosphere with fine particles, or aerosols that initially cooled the planet. But, more importantly, the eruptions also would have spewed carbon dioxide and other greenhouse gases to produce long-term warming that led to the first of the two mass extinctions.
6.0 magnitude earthquake strikes Kuril Islands
September 9, 2012 – KURIL ISLANDS – On Sunday, two earthquakes hit Kuril Islands in the Russian Far East. The first quake of 6.0 point magnitude on the Richter scale was recorded near the island of Paramushir, says seismological station in the city of Severo-Kurilsk. Glass-ware ringed in cupboards for ten seconds, and ceiling lamps rocked. The second earthquake with a magnitude of 5.1 points in Richter scale took place in the deep-water Kurilo-Kamchatka trench. The epicenter was located 270 kilometers east of the city of Kurilsk on the island of Iturup. There was no tsunami warning.
Thousands Evacuated After Volcano In Nicaragua Erupts
Sep 9, 2012 – 6:46:49 PM
Chinandega, Nicaragua – More than 1,500 people have been evacuated after a volcano in western Nicaragua erupted Saturday, shooting gas and ash 2 1/2 miles into the sky, government officials said.
Explosions at San Cristobal Volcano — located in the department of Chinandega about 65 kilometers (40 miles) south of the Honduran border and 130 kilometers north of the capital, Managua — began around 8:45 a.m. Saturday, according to an assessment from SINAPRED, Nicaragua’s federal emergency and disaster management agency.
“We have to be careful and take all appropriate measures for the families that are there and families from neighboring towns,” first lady Rosario Murillo told the EL19 government-run newspaper. She said 400 families have been moved.
“I have seen it bring ashes, but not like now,” Jose Espinoza, who lives near the volcano, said. “It surprised us because it is a powerful volcano and to see it like this would make anyone panic.”
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Jacinta Carazo, another resident, told CNN that an eruption in 2006 brought a lot of mud but this one was mostly ash.
“It got dark,” she said.
Neither Espinoza nor Carazo has evacuated nor do they want to leave.
A story linked off Nicaraguan President Daniel Ortega’s website indicated 20,000 people in surrounding towns could be affected.
About 3,000 people in five communities were already seeing gases and other effects after three large explosions on Saturday, SINAPRED director Guillermo Gonzalez said, according to the El Pueblo Presidente website.
Authorities say the main risk is the mix of rain, ash and gas that could affect the health of residents.
School classes have been suspended in Chinandega department through Sunday, education official Jose Tremino said.
At about 1,745 meters (5,725 feet), San Cristobal is Nicaragua’s tallest volcano, and is part of a complex consisting of five volcanic edifices, according to the Smithsonian Museum of Natural History.
Prior to Saturday, the last known eruption of San Cristobal — which is also known as El Viejo — was in 2011, the museum said.
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