Another Large Earthquake Off Coast Of Sumatra Likely

ScienceDaily (Dec. 4, 2008) — The subduction zone that brought us the 2004 Sumatra-Andaman earthquake and tsunami is ripe for yet another large event, despite a sequence of quakes that occurred in the Mentawai Islands area in 2007, according to a group of earthquake researchers led by scientists from the Tectonics Observatory at the California Institute of Technology (Caltech).

"From what we saw," says geologist Jean-Philippe Avouac, director of the Tectonics Observatory and one of the paper's lead authors, "we can say with some confidence that we're probably not done with large earthquakes in Sumatra."

The devastating magnitude 9.2 earthquake that occurred off the western coast of Sumatra on December 26, 2004—the earthquake that spawned a lethal tsunami throughout the Indian Ocean—took place in a subduction zone, an area where one tectonic plate dips under another, forming a quake-prone region.

It is that subduction zone that drew the interest of the Caltech-led team. Seismic activity has continued in the region since the 2004 event, they knew. But have the most recent earthquakes been able to relieve the previous centuries of built-up seismic stress?

Yes . . . and no. Take, for instance, an area just south of the 2004 quake, where a magnitude 8.6 earthquake hit in 2005. (That same area had also been the site of a major earthquake in 1861.) The 2005 quake, says Avouac, did a good job of "unzipping" the stuck area in that patch of the zone, effectively relieving the stresses that had built up since 1861. This means that it should be a few centuries before another large quake in that area would be likely.

The same cannot be said, however, of the area even further south along that same subduction zone, near the Mentawai Islands, a chain of about 70 islands off the western coasts of Sumatra and Indonesia. This area, too, has been hit by giant earthquakes in the past (an 8.8 in 1797 and a 9.0 in 1833). More recently, on September 12, 2007, it experienced two earthquakes just 12 hours apart: first a magnitude 8.4 quake and then a magnitude 7.9.

These earthquakes did not come as a surprise to the Caltech researchers. Caltech geologist and paper coauthor Kerry Sieh, who is now at the Nanyang Technological University in Singapore, had long been using coral growth rings to quantify the pattern of slow uplift and subsidence in the Mentawai Islands area; that pattern, he and his colleagues knew, is the result of stress build-up on the plate interface, which should eventually be released by future large earthquakes.

But was all that accumulated stress released in 2007? In the work described in the Nature letter, the researchers analyzed seismological records, remote sensing (inSAR) data, field measurements, and, most importantly, data gathered by an array of continuously recording GPS stations called SuGAr (for Sumatra Geodetic Array) to find out.

Their answer? The quakes hadn't even come close to doing their stress-reduction job. "In fact," says Ali Ozgun Konca, a Caltech scientist and the paper's first author, who did this work as a graduate student, "we saw release of only a quarter of the moment needed to make up for the accumulated deficit over the past two centuries." (Moment is a measure of earthquake size that takes into account how much the fault slips and over how much area.)

"The 2007 quakes occurred in the right place at the right time," adds Avouac. "They were not a surprise. What was a surprise was that those earthquakes were way smaller than we expected."

"The quake north of this region, in 2005, ruptured completely," says Konca. "But the 2007 sequence of quakes was more complicated. The slippage of the plates was patchy, and it didn't release all the strain that had accumulated."

"It was what we call a partial rupture," adds Avouac. "There's still enough strain to create another major earthquake in that region. We may have to wait a long time, but there's no reason to think it's over."

Their findings were published in a letter in the December 4 issue of the journal Nature.

Other authors on the paper include Anthony Sladen, Aron J. Meltzner, John Galetzka, Jeff Genrich, and Don V. Helmberger from Caltech; Danny H. Natawidjaja from the Indonesian Institute of Science (LIPI); Peng Fang and Yehuda Bock from the Scripps Institution of Oceanography in La Jolla; Zhenhong Li from the University of Glasgow in Scotland; Mohamed Chlieh from the Université de Nice Sophia-Antipolis in France; Eric J. Fielding from the Jet Propulsion Laboratory; and Chen Ji from the University of California, Santa Barbara.

The work was supported by funding from the National Science Foundation and the Gordon and Betty Moore Foundation.

Journal reference:

1. . Partial rupture of a locked patch of the Sumatra megathrust during the 2007 earthquake sequence.Nature, December 4, 2008

Adapted from materials provided by California Institute of Technology, via EurekAlert!, a service of AAAS.

Source :http://www.sciencedaily.com/releases/2008/12/081203131042.htm

Cyclones in the Indian Ocean: Facts and figures

Greg O'Hare explains the what, why, when and how of cyclones, and reviews their effects in South Asia.

'Tropical cyclone' is the general term for low-pressure atmospheric circulations in the tropics. These have anticlockwise rotating winds in the northern hemisphere and clockwise rotating winds in the southern hemisphere.

Low to moderate intensity tropical cyclones bring much needed rain for agriculture around the northern Indian Ocean. But, when tropical cyclones strengthen, they can bring great loss of life and property to the region.

Cyclonic structures

All tropical cyclones have low atmospheric pressure at ground level, and a vortex of converging winds and rising air. They all have extensive rain-bearing layered clouds (deep nimbostratus) and towering vertically extensive cumulonimbus rain-bearing clouds. Yet despite these common features, tropical cyclones in South Asia vary greatly in size, frequency and intensity, and have varying effects on the land they cross.

Table 1 shows four types of tropical cyclones. These weather systems form a continuum — if conditions are right and surface pressure continually falls, a tropical low can develop over time into a tropical depression, then into a tropical storm and eventually into an intense tropical storm. In South Asia, as in the western world, the most intense tropical storms are called hurricanes. But, confusingly, the most intense circulations in the Pacific are called cyclones.

 

Type of tropical cyclonic system	Speed (m/sec)	Height (km)	Duration (days)	Width (km)	Frequency	Rainfall (cm)
Low	<8	2–4	1–3	150–300	frequent	5–10
Depression	8–17	4–8	2–5	250–500	common	10–20
Storm	17–32	8–10	3–10	300–600	occasional	20–50
Hurricane	>32	8–12	5–7	400–1000	rare	50–150

Table 1: Types of tropical cyclones in India [1]

Lows and depressions are the most frequent systems and produce most of India's annual rainfall (about 890mm). Indeed, with their lower intensity rainfalls, they form the backbone of South Asian agriculture.

But when a long series of deep tropical depressions occur (lasting three to four weeks), the cumulative rainfall can lead to extensive flooding, dam collapses and landslides. In southern Bangladesh, more than 100 families were washed away when a dam collapsed in July 2004. In 2008, summer monsoon flooding and landslides in India (especially in Bihar State) killed 1065 people and affected approximately 7.9 million people.

How do hurricanes form?

Tropical cyclones affecting south Asia originate over surrounding oceans, especially in the Bay of Bengal. They require at least five conditions to form and develop: low pressure at the surface; abundant moist air capable of convective or upward movement in the atmosphere; ocean surface temperatures over 26–27 degrees Celsius; small wind shear — the rate at which wind strength and direction change with height in the atmosphere — (especially for the taller more intense systems); and the power of the Earth's rotation to spin the system into a rotating vortex.

Tropical cyclones in South Asia derive their main energy from intense evaporation over warm water — not, as in mid-latitude cyclones, from contrasting temperatures between cold and warmer air masses.

Water vapour, evaporated from the sea, is drawn into the developing cyclone. As the rising air within the cyclone cools, the evaporated moisture becomes cloud, forming billions of tiny water droplets. Converting the water vapour to water droplets releases a great amount of (latent) heat, providing energy that helps invigorate and maintain the cyclone's development.

Timing and monsoon regulation

The tropical cyclones that influence South Asia are part of the regional monsoon wind system. The South Asian monsoon has moist south-westerly winds blowing from the southern oceans over the South Asian continental land mass in summer, and dry north-easterly winds blowing in the opposite direction in winter.

The differential heating of land and sea drives this movement. In the summer, the land heats up more quickly than the oceans, producing low pressure over land and high pressure at sea. Winds blow from high to low pressure, bringing strong, moist winds from the oceans towards South Asia. During the winter months, the differential heating and pressure systems are reversed, and strong dry north-easterly winds end up blowing from South Asia towards the southern oceans.

Most rainfall over the region comes in the summer months (June to September) from relatively weak but frequent tropical lows and depressions. Driven by monsoon winds, these systems eventually move over land along the west coast of India, but more frequently affect the eastern coast of India and Bangladesh.

The more intense tropical storms and hurricanes, which also tend to form mainly in the Bay of Bengal, often occur as the wet summer changes to a dry winter monsoon (October to November) when wind shear is low. Powerful cyclones, which tower up into the atmosphere, do not easily form during the main monsoon season (June to September) because high wind shear easily destabilises them, knocking them over.

Hurricane damage

The areas of South Asia most vulnerable to hurricanes are the low-lying coastal regions around the Bay of Bengal (Bangladesh, Eastern India and Myanmar). These are the first areas storms hit when they reach land and are also some of the most agriculturally fertile — and densely populated — areas in South Asia, including coastal river deltas like the Godavari, Ganges and Irrawaddy.

Hurricanes' high wind speeds, intense rainfalls and storm surges (unusually high sea levels) destroy life and property, and can leave areas devastated. Winds, often travelling at more than 117 kilometres per hour, remove or seriously damage flimsy housing.

High intensity rainfall over a relatively short period (up to and above 50 centimetres over three to seven days) can cause serious flooding and major crop loss. As with the less intense cyclones, such flooding can increase loss of life and property if it causes reservoir collapses and landslides.

But the most destructive part of a cyclone is the storm surge at the front of the storm pushed up to high levels as it moves inland. Storm surges from powerful hurricanes can reach two to five metres in height along the eastern coast of Andhra Pradesh in India. At the head of the Bay of Bengal, where the coastline becomes restricted, storm surges can reach a staggering 12 or 13 metres and kill many people (see Table 2).

Region	Date	Deaths
Andhra Pradesh	10 Oct 1679	20,000
Bangladesh	07 Oct 1737	300,000
Bangladesh	13 Nov 1970	500,000
Andhra Pradesh	26 Nov 1977	>10,000
West Bengal	29 Apr 1991	140,000

Table 2: Hurricane deaths in the Bay of Bengal region [1]

Hurricanes in a warming world

There is every chance that hurricanes will do more damage in South Asia in the future as population densities increase in coastal areas. The numbers of people at risk may also rise if hurricanes become more intense as the world and oceans warm up.

Some studies have found no evidence for an increase in hurricanes' frequency or intensity in the Caribbean. [2,3] Others have found little change in the frequency and intensity of hurricanes globally during the last 20 years. [4]

By contrast, other strong evidence based on good quality data has shown that in recent years hurricanes, particularly the stronger ones (categories four and five), have become more intense in all hurricane regions, including the northern Indian Ocean (Table 3). [5,6]

Basin	1975–1989		1990–2004
	No.	Percentage of all hurricanes	No.	Percentage of all hurricanes
East Pacific	36	25	49	35
West Pacific	85	25	116	41
North Atlantic	16	20	25	25
South West Pacific	10	12	22	28
Indian Ocean	24	13	57	29

Table 3: Changes in the number and percentage of category four and five hurricanes for the periods 1975–89 and 1990–2004 for different ocean basins. [5]

Vulnerable populations

The people most vulnerable to hurricanes around the world include those with limited economic resources, low levels of technology, poor information and skills, minimal infrastructure and unstable or weak political institutions (Table 4). Such groups are not fully able to prepare for, or protect themselves from, hurricanes, nor to respond and cope with their effects.

Low cast communities

Ethnic minorities

Women, especially those who may be widowed or deserted

Old men and women

Children, particularly girls

The disabled

People dependent on low incomes

People in debt

People isolated from transport, communication and health services infrastructure

Table 4: Disaster prone groups in India [1]

When a category four hurricane hit the Godavari delta region of eastern India in November 1986, various marginalised groups responded differently to the hurricane's impact. For example, poor female agricultural labourers working in flood damaged rice fields had to sell their few possessions and become maids in nearby villages, or migrate to other paddy regions in order to cope. By contrast, poor fishing communities along the delta coast (where many people died due to storm surges) relied on close family and kinship links for money, food and fishing tackle to get over the storm's effects.

Basic precautions

There are ways to make the likely rise in hurricane impact less damaging in the region. One solution is to improve the physical structures that protect people. For example, many new hurricane shelters are being built along the coast of eastern India. Deaths from hurricanes will certainly decline if more local people can be encouraged to use the shelters.

Improvements in government-built early warning and evacuation procedures will also help save lives, although access to these may be limited because many communities suffer from isolation, language barriers, and poor transport and communication (including radio/phone) systems. Still, because of improvements, albeit slow, in the introduction and uptake of such systems, hurricanes that would have killed 10,000 people in Andhra Pradesh in the late 1970s kill around 1,000 today.

Governments and international agencies can also do a lot more to mitigate storm impacts through rehabilitation policies, such as providing basic relief (food, shelter, cooking oil and clean water). It is also crucial that affected communities get better health services, since the spread of water-borne diseases (like typhoid and dysentery) after hurricanes often kills far more people than flooding, landslides or even storm surges.

Greg O'Hare is a professor of geography at the University of Derby, United Kingdom.

REFERENCES

[1] O'Hare, G. Hurricane 07b in the Godavari Delta, Andhra Pradesh, India: vulnerability, mitigation and the spatial impact. The Geographical Journal167, 23–38 (2001)

[2] Michaels P.J., Knappenberger, P.C. & Davis, R.E. Sea surface temperatures and tropical cyclones in the Atlantic basin. Geophysical Research Letters 33, (2006)

[3] Hoyos, C.D., Agudelo, P.A., Webster, P.J. et al. Deconvolution of the factors contributing to the increase in global hurricane intensity. Science 312, 94–97 (2006)

[4] Klotzbach, P.J. Trends in global cyclone activity over the past 20 years (1986-2005) Geophysical Research Letters 33, (2006)

[5] Webster P.J., Holland, G.J., Curry, J.A. et al. Changes in tropical cyclone number, duration and intensity in a warming environment. Science 309, 1844–1846 (2005)

[6] Elsner, J.B., Kossin, J.P. & Jagger, T.H. The increasing intensity of the strongest tropical cyclones. Nature 455, 92–95 (2008)

 

 

Earth cracks in UP seismic related: Expert

Motion of a massive granitic body under the earth could be the probable reason behind alarming cracks on the earth crust that have created a panic like situation in northern Indian state of Uttar Pradesh (UP).
“If this granitic craton motion is changed due to some tectonic reason, one may see subsidence at large scale—since a fault is present along Kanpur-Lucknow—there could be danger of large surface deformation,” cautioned an US based Indian scientist Ramesh Singh.
The effect of motion of this block will be reflected in widespread cracks, he said. Singh is a Professor at George Mason University in Washington and vice chair of GeoRisk Commission of the International Union of Geodesy and Geophysics.
He further said that the Government of India should monitor seismic activities in the area to avert any major disaster due to this motion.
Singh, who had extensively studied the seismology in this part of UP during his stint at IIT Kanpur as a Professor said if the orientation of such long cracks was in the east-west direction, then the cracks could be due to stress on the surface of the earth due to motion of this massive craton (granitic body) exposed near Jhansi.
He said this massive body underlying the region is inclined towards northeast with depth reaching 300-500 metres near Kanpur and 1,200 metres in Lucknow.
About 18 months back, scientists observed a shift in the position of the Sangam—the confluence of rivers Ganges and Yamuna and mythical Saraswati near Allahabad—and thought it was due to the sediment load in the rivers or due to plate motion, Singh said.
“Now, the appearance of large widespread cracks is clear evidence of neo-tectonic activities associated with the building of stress in this region and we must monitor seismic activities along Kanpur-Lucknow and Moradabad faultlines,” the Professor said.
Singh said he initially suspected that the cracks might be due to subsidence as a result of excessive groundwater withdrawal but ruled it “since the cracks were seen on a regional scale in many parts of Kanpur, Hamirpur, and Allahabad.”
The formation of cracks on the earth continues to affect various districts of UP and two villages near Lucknow are the latest to witness long fissures on the surface.
Fields in Kakori block’s two villages, Dullu Khera and Vader Khera, about 10 km from Lucknow, have developed wide cracks up to 250 metres long, officials said.
Besides the villages in Lucknow district, six districts of Uttar Pradesh have been witnessing this phenomenon for about a week.

Source: http://www.igovernment.in/site/earth-cracks-in-up-seismic-related-expert/

Active Submarine Volcanoes Found Near Fiji

ScienceDaily (June 20, 2008) — Several huge active submarine volcanoes, spreading ridges and rift zones have been discovered northeast of Fiji by a team of Australian and American scientists aboard the Marine National Facility Research Vessel, Southern Surveyor.

On the hunt for subsea volcanic and hot-spring activity, the team of geologists located the volcanoes while mapping previously uncharted areas. Using high-tech multi-beam sonar mapping equipment, digital images of the seafloor revealed the formerly unknown features.
The summits of two of the volcanoes, named ’Dugong’, and ’Lobster’, are dominated by large calderas at depths of 1100 and 1500 metres.
During the six-week research expedition in the Pacific Ocean, scientists from The Australian National University (ANU), CSIRO Exploration & Mining and the USA, collaborated to survey the topography of the seafloor, analysing rock types and formation, and monitoring deep-sea hot spring activity around an area known as the North Lau Basin, 400 kilometres northeast of Fiji.
The voyage’s Chief Scientist, ANU Professor Richard Arculus describes the terrain – the result of extreme volcanic and tectonic activity – as spectacular. “Some of the features look like the volcanic blisters seen on the surface of Venus,” he says.
“These active volcanoes are modern day evidence of mineral deposition such as copper, zinc, and lead and give an insight into the geological make-up of Australia,” he says.
“It provides a model of what happened millions of years ago to explain the formation of the deposits of precious minerals that are currently exploited at places like Broken Hill and Mt Isa. It may also provide exploration geologists with clues about new undiscovered mineral deposits in Australia.
“These deep-sea features are important in understanding the influences that have shaped not only our unique continent but indeed the whole planet,” Professor Arculus says.
Such discoveries highlighted man’s lack of knowledge about the world’s oceans. “We know more about the surface of Mars than we know about the ocean seafloor,” Professor Arculus says.
CSIRO’s Director of Research Vessels, Captain Fred Stein, says the expedition was a humbling experience. “It was a reminder that at the beginning of the 21st century it is still possible – on what is often regarded as a thoroughly explored planet – to discover a previously unknown massif larger than Mt Kosciuszko,” he says.
“We are fortunate that we can offer the scientific capability of the Southern Surveyor to Australian scientists. It’s the only Australian research vessel that can provide the opportunity to conduct such valuable research to make these kinds of discoveries possible.”

Source: http://www.sciencedaily.com/releases/2008/06/080619093259.htm

Chinese scientists call for better quake prediction

BEIJING] Scientists in China are calling for improvements in earthquake prediction, including the establishment of an early-warning system and methods for scientists to share quake information.
The calls come after the Sichuan earthquake — the country's most serious earthquake in 30 years — hit on 12 May (see China displays openness in earthquake response).
Ni Sidao, a professor of geophysics at the University of Science and Technology of China, says that although current scientific methods cannot accurately predict an earthquake, an early-warning system could alert people to leave for open spaces before buildings are destroyed.
Ni made his remarks last week (25 May) alongside other scientists at the China Science and Humanities Forum in Beijing, operated by the Graduate University of the Chinese Academy of Sciences.
He said that P waves — early-arriving non-destructive seismic waves — can be used to detect and calculate the scale of an earthquake within ten seconds with the aid of computers.
In the case of Sichuan, the later-arriving, destructive seismic waves (S waves) took 30 seconds to reach Beichuan — the most seriously hit county, 90 kilometres north of the epicentre — and nearly 100 seconds to reach Qingchuan County, 200 kilometres from the epicentre.
People in Beichuan could have had a ten-second warning of the earthquake with an early-warning system, allowing some to move outdoors and trains to stop to avoid derailing, said Ni.
But he admitted that current seismic monitoring stations in most parts of China are too isolated to form a warning network.
Ren Luchuan, a senior researcher at China Earthquake Networks Centre (CENC), welcomes Ni's suggestions, but says such a system is very difficult to operate.
"[The time difference between P and S waves] is so short that it is very hard to establish a system to notify residents," he told SciDev.Net, though he says such a system could be used for key sites such as nuclear power stations, which could close reactors.
Longer-term prediction seems to be just as fraught with problems.
In the latest issue of the Chinese language journal Science and Technology Review (28 May), Wu Lixin from the Chinese University of Mining and Technology, Beijing, and colleagues report an abnormal temperature rise in the thermal satellite images of the eastern front of Qinghai–Tibet plateau — the fault that caused the earthquake — 20 days before the Sichuan earthquake.
The authors suggested this rise could be caused by tectonic plate movement, and could be an indicator for earthquake prediction.
But Ren says many factors could cause the abnormal temperature increases, leading to uncertainty in using temperature change to predict earthquakes.
In a separate article published in the same issue, however, Wu writes that there should be more intensive, accurate and consistent analyses of thermal satellite images, and that these should be frequently checked against seismic wave monitoring.
In addition, Wu says an earthquake information sharing system should be established, so that general researchers can analyse or input data about abnormal observations into a system for professional seismologists to screen.

Source : http://www.scidev.net/en/news/chinese-scientists-call-for-better-quake-predictio.html

RISING TEMPERATURES, MORE EXTREME WEATHER

The planet's temperature is rising, and it's rising at an accelerated pace that most scientists say is down to manmade factors. As the climate changes, they predict it will lead to more dramatic weather and disasters - not just droughts, but storms, floods and spreading disease too.
Climate change increases risk of conflict 250 million people could be displaced by climate-related disasters by 2050 The world's poor - the most vulnerable to climage change - need help adapting

Statistics from the International Disaster Database show a steep rise in weather-related disasters since the middle of the 20th century, and the number of people affected is also going up. The Intergovernmental Panel on Climate Change (IPCC) says the world can expect more heatwaves and droughts, heavier rains, stronger storms and rising sea levels due to global warming caused by emissions of greenhouse gases.

Africa, Latin America and parts of Asia - where the climate is already more extreme and arid regions are common - are likely to be most affected as rainfall declines and its timing becomes less predictable. Large numbers of people could be forced to find new homes as their living environments are submerged, or food and water become scarce. British-based aid and development agency Christian Aid quotes a scientist's estimate that up to 250 million people could be displaced by climate-related disasters by the middle of the century. And experts say diseases will spread to new places as the planet changes. In 2007, the Nobel Peace Prize was awarded jointly to the IPCC and former U.S. Vice President Al Gore for their work in building up and spreading knowledge about climate change. This underlined growing awareness of the potential impact climate change could have on security. Most experts say tensions caused by the environmental impact of climate change won't necessarily lead to conflict - but where they add to or make other stresses worse, there is an increased risk of violence. There's intense debate and a wide range of competing ideas on how to tackle what could be the most important issue of our time. Many developing countries believe richer nations should make greater commitments to curbing their carbon emissions, and provide more funding to help them adapt to climate change.
In December 2007, at a major meeting in Bali, nearly 200 nations agreed to launch negotiations on a new pact to follow the Kyoto Protocol, which binds rich nations to cap emissions of greenhouse gases until 2012. The United States is the only industrialised country that has not signed the Kyoto Protocol. Aid agencies are also waking up to the impact of climate change on their projects and the communities with which they work. Increasingly, they are helping local people reduce the risk of climate-related disasters, and calling for more international support to cope with the negative consquences of climate change.

Source: Reuters

Satellite data reveals seismic link to volcanoes

Local earthquakes boost volcanic activity in Indonesia, researchers have shown using satellite data. The finding could, they say, point to a predictive role for satellite imaging.
Volcanic activity in two ongoing eruptions, Merapi and Semeru on the Indonesian island of Java, increased following a local earthquake in May 2006 that measured 6.4 on the Richter scale. The flare-up began three days after the earthquake and lasted for nine days.
The researchers, led by Andrew Harris of the University of Hawaii, used thermal imaging data from an instrument on a NASA (the US National Aeronautics and Space Administration) satellite.
This provides near real-time data on global hotspots such as volcanic eruptions and wildfires. The team used data from a 35 day period, including the time of the earthquake.
"We found clear evidence that the earthquake caused both volcanoes to release greater amounts of heat, and lava emission surged to two to three times higher than prior to the tremor," Harris told NASA.
The researchers believe that the changes in eruption were due to seismic waves from the earthquake travelling to the area round the volcano and triggering an increased flow of molten rock.
But Dave Rothery, a vulcanologist in the Department of Earth Sciences at the UK-based Open University, warned that the study’s focus — one earthquake stimulating two volcanoes — could be a coincidence and more examples are needed.
The researchers say the work shows that satellite imaging could play a predictive role in eruptions, ultimately alerting people living near volcanoes to increased volcanic activity.
"I'm not sure we're up to early warning yet," Harris told SciDev.Net. "But immediately once an eruption begins we can detect its thermal signature, post its location on our global map, and perhaps alert people via automated email."
Rothery added that anyone with internet access could identify when volcanic activity is increasing in their area, information which could be "factored into decisions about evacuation".
The research was published in Geophysical Research Letters.

Source:

http://www.scidev.net/News/index.cfm?fuseaction=readNews&itemid=3553&language=1

Study helps predict big Mediterranean quake

LONDON, March 9 (Reuters) - Scientists have found evidence that an overlooked fault in the eastern Mediterranean is likely to produce an earthquake and tsunami every 800 years as powerful as the one that destroyed Alexandria in AD 365.
Using radiocarbon dating techniques, simulations and computer models, the researchers recreated the ancient disaster in order to identify the responsible fault, they said in a study published in the journal Nature Geoscience on Sunday.
"We are saying there is probably a repeat time of 800 years for this kind of earthquake," said Beth Shaw, a seismologist at the University of Cambridge, who led the study.
Scientists study past earthquakes in order to determine the future likelihood of similar large shocks. Identifying the fault for the AD 365 earthquake and tsunami is important for the tens of millions of people in the region, Shaw said.
The fault close to the southwest coast of Crete last produced a big enough quake to generate a tsunami about 1300, which means the next powerful one could come in the next 100 years, she added in a telephone interview.
Shaw and her colleagues calculate the likely intervals by measuring the motion of either side of the fault to gauge how often such large earthquakes would have to occur to account for that level of motion, she said.
Their computer model suggested an 8 magnitude quake on the fault would produce a tsunami that inundates the coastal regions of Alexandria and North Africa, the southern coast of Greece and Sicily all the way up the Adriatic to Dubrovnik, Shaw said.
This would be similar to the ancient quake in AD 365 that caused widespread destruction in much of Greece and unleashed a tsunami that flooded Alexandria and the Nile Delta, likely killing tens of thousands of people, she said.
"This is consistent with the historical record of the tsunami," she said. (Reporting by Michael Kahn; Editing by Janet Lawrence)

Source: http://www.alertnet.org/thenews/newsdesk/L07804229.htm

Increased Hurricane Losses Due To More People, Wealth Along Coastlines, Not Stronger Storms

ScienceDaily (Mar. 1, 2008) — A team of scientists have found that the economic damages from hurricanes have increased in the U.S. over time due to greater population, infrastructure, and wealth on the U.S. coastlines, and not to any spike in the number or intensity of hurricanes

“We found that although some decades were quieter and less damaging in the U.S. and others had more land-falling hurricanes and more damage, the economic costs of land-falling hurricanes have steadily increased over time,” said Chris Landsea, one of the researchers as well as the science and operations officer at NOAA’s National Hurricane Center in Miami. “There is nothing in the U.S. hurricane damage record that indicates global warming has caused a significant increase in destruction along our coasts.”
In a newly published paper in Natural Hazards Review, the researchers also found that economic hurricane damage in the U.S. has been doubling every 10 to 15 years. If more people continue to move to the hurricane-prone coastline, future economic hurricane losses may be far greater than previously thought.
“Unless action is taken to address the growing concentration of people and property in coastal hurricane areas, the damage will increase by a great deal as more people and infrastructure inhabit these coastal locations,” said Landsea.
The Natural Hazards Review paper, “Normalized Hurricane Damage in the United States: 1900-2005,” was written by Roger A. Pielke Jr. (University of Colorado), Joel Gratz (ICAT Managers, Inc.), Chris Landsea, Douglas Collins (Tillinghast-Towers Perrin), Mark A. Saunders (University College London), and Rade Musulin (Aon Re Australia).
The team used two different approaches, which gave similar results, to estimate the economic damages of historical hurricanes if they were to strike today, building upon the work published originally by Landsea and Pielke in 1998, and by Collins and Lowe in 2001. Both methods used changes in inflation and wealth at the national level. The first method utilized population increases at the county coastal level, while the second used changes in housing units at the county coastal level.
The results illustrate the effects of the tremendous pace of growth in vulnerable hurricane areas. If the 1926 Great Miami Hurricane were to hit today, the study estimated it would cause the largest losses at $140 billion to $157 billion, with Hurricane Katrina second on the list at $81 billion.
The team concludes that potential damage from storms – currently about $10 billion yearly – is growing at a rate that may place severe burdens on exposed communities, and that avoiding huge losses will require a change in the rate of population growth in coastal areas, major improvements in construction standards, or other mitigation actions.
Adapted from materials provided by National Oceanic And Atmospheric Administration.

Source:http://www.sciencedaily.com/releases/2008/02/080228074324.htm