Science Niche » Climatology

A major earthquake in Haiti

admin — Thu, 14 Jan 2010 10:04:55 +0000

Yesterday Tuesday, a violent earthquake, a magnitude of 7, struck Haiti. The damage is considerable, especially in Port-au-Prince, the capital. The number of victims is unknown at this time. He was 16 h 53 local time this Tuesday, January 12, 2010 (21 h 53 in time universal, or 22 h in 53 French time) when the earth shook violently.

The epicenter, unfortunately, is only twenty kilometers from the capital, Port-au-Prince. According to the PTWC (Pacific Tsunami Warning Center), which depends on the NOAA, the magnitude was 7.1, or 7.0 according to the USGS, high energy, which corresponds to an earthquake called “major”. It is the same as that of the earthquake that rocked Sumatra September 30, 2009. The undersea earthquake that caused the 2004 tsunami in the Indian Ocean himself had reached 9.3.

Two aftershocks of magnitudes 5.9 and 5.5. The island of Santo Domingo, which is also the Dominican Republic, had not experienced such an event for 200 years.

Major volcanic eruption is preparing Does Indonesia

admin — Tue, 22 Dec 2009 07:10:06 +0000

The assumption seems plausible. Already in 1835, Charles Darwin had speculated on the possibility of volcanic eruptions triggered by earthquakes. Today, the volcanologist David Pyle, University of Oxford (UK) and colleagues Sebastian Watt Tamsin Mather and reviewed data covering the last 150 years of earthquakes along the Chilean coast, there including two major earthquakes in 1906 and 1960 in southern Chile, the latter being the largest in recorded history.

In the journal Earth and Planetary Science Letters, the team shows that the frequency of eruptions of 15 volcanoes located within a thousand kilometers of the epicenters in the year that followed two tremors had quadrupled. “We are confident of our findings, says David Pyle. We have never seen such an increase of activity without it being associated with major earthquakes.

Based on this finding, David Pyle suggests that scientists are trying to trace the beginnings of volcanic events in Indonesia consecutive great earthquake of 2004 and the two shocks of 2007. Four outbreaks have occurred among the 36 active volcanoes on the island of Sumatra, suggesting a link between cause and effect.

The publication should help scientists better understand the mechanisms linking earthquakes to volcanic eruptions, says geologist Thomas Parsons of the U.S. Geological Survey in Menlo Park, California. It also stresses the importance of further studies in this area in the hope one day to improve scientists’ ability to predict eruptions.

A new earthquake looms large does in Sumatra?

Kerry Sieh and his colleagues from the California Institute of Technology in Pasadena, in turn, were based on examination and growth rings of corals growing off the Mentawai Islands to trace the history of earthquakes in Sumatra during last seven centuries. During earthquakes, the seafloor rises locally by lowering the water level. Corals do not grow in height but then the sides and the growth rings retain the trace.

The team of scientists has identified several series of large earthquakes have succeeded in this place with a frequency of 200 years in the fourteenth century to the late sixteenth century and from 1797 to 1833. It is logically possible that the great earthquake of September 2005 is also the first in a series to come next.

An uncertainty of several decades to more than a century, however, prevents predict the arrival of the next episode, but this risk through the tsunami it triggered, be very destructive of life as destruction of property.

Earth seen from space: Hawaii Pacific hotspot

admin — Tue, 22 Dec 2009 07:05:14 +0000

All the main islands of this archipelago is formed by volcanic mountain peaks, which are formed there are several million years when the rock basaltic melt has escaped from a fault in the seafloor. Located above a hot spot of magma at the heart of the Pacific Plate, the islands of Hawaii ((Hawaii in English, Hawai’i in Hawaiian) has some of the largest volcanoes inactive and active world.

At a height of 4205 m, the volcano Mauna Kea (the most northern of the two volcanoes of the Big Island of Hawaii) is the culmination of the archipelago. The height of the mountains is generally measured from sea level, but if measured from the ocean floor, Mauna Kea reaches 10,230 m, making it the highest mountain of the Earth taken from the bottom up. Due to special weather conditions and sky transparency, many of the most powerful telescopes in the world have been installed. It includes Keck I and II, Gemini North, Subaru, and a radio telescope network Very Long Baseline Array.

Mauna Loa, located south of Mauna Kea, is the largest volcano in the world by volume (about 40,000 km Â³). He woke up 33 times since the first eruption documented in 1843 and is one of the most active volcanoes in the world. Its last eruption was in 1984.

Due to the strong activity of Mauna Loa, scientists continuously monitor the volcano in search of any sign ahead of his wake. The radars in orbit, as the instrument Asar (Advanced Synthetic Aperture Radar) on board of Envisat, allow them to track small changes in the movements of lands that enhance their ability to predict volcanic eruptions.

Radar imagery reveals the angry princess

The interferometric radar mathematically combining different radar images – acquired as close as possible to the same point in space at different times – to create models digital elevation terrain and reveal changes between image acquisitions that would be otherwise undetectable.

Kilauea, located on the south-east of the island, around the areas in red and pink, is another of the most active volcanoes on Earth. The current volcanic episode began in 1983 and has not stopped since. According to local legends, Kilauea is the domain of Pele, the Hawaiian goddess of volcanoes, and eruptions occur when the goddess is angry.

The image below was created by combining three images taken over the same area by the radar Asar of Envisat on 27 March 2006, April 16, 2007 and January 21, 2008 and each associated with a code of color. The colors appearing on the image resulting from variations between any of the shots.

Earth seen from space: the land of lakes and volcanoes

admin — Tue, 22 Dec 2009 07:03:01 +0000

The Gulf of Fonseca on the Pacific coast (in the form of leg, left on the picture below article) is a natural port shared between Nicaragua, El Salvador and Honduras. Cosiguina Peninsula, bordering the Gulf South, was formed by sand, ash and lava from the volcano Cosiguina, located at its tip.

It exploded with such violence in 1835 that a third of its cone was blown and ash fell back to 1,400 miles away in Jamaica and Mexico City. Cosiguina The lagoon is located inside the volcano.

Many volcanoes are located between the Gulf of Fonseca and Lake Managua (a little more right, colored green). The capital of Nicaragua, Managua, is located on the south shore of the lake.

The lake covered with clouds, the bottom of the image is Lake Nicaragua. With its 8157 kilometers 2, it is the largest lake of water fresh from Central America. It contains shark Bulldogs, the only shark in the world able to survive in freshwater.

The beige form the middle of the east coast of the Pearl Lagoon, which covers 518 km 2, while the dark area in the north is the Cordillera Isabella, which rises to over 2,100 m.

Penultimate round for the post-Kyoto

admin — Mon, 14 Dec 2009 06:12:56 +0000

More than 1,600 written contributions by 80 experts from all countries on climate change will be presented from Tuesday at the IPCC conference in Copenhagen, which could be the last chance. In December, the agreement will replace the Kyoto takes effect. The objective of this meeting is to update the scientific data collected since the latest findings presented in 2007 by the IPCC (Intergovernmental Panel on Climate Change, Nobel Peace in 2007 with Al Gore). This dede prepare the fifteenth UN conference on climate to be held next December in Copenhagen ever. The stakes are high since the last round will be the last international meeting to prepare the roadmap for a policy of reduction of emission of greenhouse gas emissions from 2012, that is to say the expiry of the Kyoto agreement.

Meanwhile, climatologists, glaciologists, oceanographers but also epidemiologists and economists have presented some 1,600 reports, which will be carefully examined from this Tuesday, March 10 for three days to answer key questions about the impact of global warming. And the trend is not optimistic …

For if the reduction of gas emissions greenhouse 25 to 40% by 2020 already seemed random, we realize, by reading the texts currently on the table, that the historical responsibility of industrialized countries tends to be, if not erased, at least blurred. While the goals of emission reduction agreements under the IPCC in 2007 may be conceived without calling into question the radical doctrines of growth, but rather to a monetization of CO 2 that said rich countries were directed, establishing a true “fellowship of carbon” with purchase and sale of pollution permits …

Forecasts again

While scientists agreed to a rise in sea level of 15 to 58 centimeters at the end of the century, the observation of melting ice polar indicates that these figures are revised upwards from 10 to 20 centimeters . This data, as well as increasing the number of people displaced as a result of this change will be a high priority of the IPCC conference that opened.

Rajendra Pachauri, chairman of the IPCC, and the British economist Nicholas Stern had already launched a warning at the last conference two years ago, and announced including “disruptions in economic activity and social (…) a similar magnitude to those who followed the biggest wars.

Tropical forests absorb more CO2 than previously believed

admin — Mon, 14 Dec 2009 06:10:02 +0000

The good news, an international study has shown that rainforests store more carbon than they release. They now absorb almost one fifth of emissions of human carbon dioxide. Each year, humans and their activities release 32 billion tonnes of carbon dioxide (or carbon dioxide), according to IPCC data. However, there are only 15 billion in the atmosphere, contributing to global warming. What happens to the rest? Scientists are still debating the general mechanics of carbon cycle and some of its workings are still poorly understood. After the oceans, the forests of tropical Africa and America (in which case we speak of neotropical forest) course play a major role, by their scope and intense biological activity. But, quantitatively, the question of their influence is always asked.

When a tree grows, it produces its timber using carbon dioxide from the air and store carbon as well. It breathes and lose leaves or branches, then quickly returns a portion of this carbon. What happens when he is old? It grows more slowly or not at all. And when he dies? He falls and billions of bacteria, fungi and of insects are responsible for crunching the deadwood, reloading of carbon in the atmosphere. The increase in atmospheric levels of carbon dioxide due to human activity, which promotes plant growth, increases does the storage capacity of trees? Finally, the forest is it a carbon sink? And if so, what size?

Clearly, the problem is different depending on latitude. For regions with a temperate climate, a recent study even showed that reforestation could warm the atmosphere.

Reducing deforestation is a key determinant

In 1998, a team had shown that the Amazon forest carbon amassed more she relaxed the death of trees. This function of carbon sinks was demonstrated in 38 of 50 sites studied. Numerical result announced by the team during the past few decades, each hectare of forest Neotropical would have absorbed 0.71 + / – 0.34 tonne of carbon each year.

The question was posed to the forests of tropical Africa. An international team led by Simon Lewis, University of Leeds, just answer them. Yes, Africa’s forests absorb some of the surplus carbon dumped into the atmosphere by human activities.

The affirmation is based on monitoring conducted for 40 years, between 1968 and 2007, about 250,000 trees of 79 sites, spread across ten African countries. This study shows that the trunks of old trees continue to grow in diameter and do more today than forty years ago. This increase represents a mass uptake of 0.6 tonnes of carbon dioxide per hectare per year. The answer – lieu – of tree growth in Africa to increase the CO 2 content is the same as the forests of Central America and south.

African forests stock each year 1.2 billion tonnes of CO2 per hectare, which led to sales of 4.8 billion tonnes for the forests of Africa and America. The authors, all the world’s tropical forests absorb about 18% of carbon dioxide emissions of human origin.

One of the co-authors, Lee White, pragmatically calculated the financial value of the 4.8 billion tons, reflecting a “realistic price of a ton” of 13 billion pounds per year, or about 15 billion euros. The fight against deforestation appears therefore, even more than previously thought, an effective way to reduce the impact of human activities on global climate. Simon Lewis concludes that the richest countries, which emit the largest quantities of carbon dioxide, should devote “significant resources to help tropical countries avoid deforestation.

120 countries gathered for a global crisis

admin — Mon, 14 Dec 2009 06:06:07 +0000

Today, one billion people short of water. In 2030, the shortage will affect half of humanity. On this finding has started in Istanbul on Fifth Global Forum on Water. For one week, 30,000 people from around the world, including 15,000 researchers and policy makers, 180 ministers and 25 heads of state will discuss a critical issue for decades to come. The Fifth Global Forum on Water, held every three years by the World Council of Water (World Water Council), has just opened in Istanbul, Turkey, ending March 22. The Secretary-General United Nations, Ban Ki-moon, said that water scarcity “may fuel wars and conflicts.”

In the Middle East between Israel and Arab countries but also around the Euphrates, between Turkey, Syria and Iraq, and many other parts of the world, sharing of water resources is at best a apple of discord at worst a source of conflict latent. He said that the precious liquid is one of the causes of the terrible war in Darfur.

A global resource to better share

Because humanity is already well and truly in a state of water shortage. Today, 1.1 billion people lack sustainable access to safe drinking water and in 2030, according to the UN, half of humanity will be in this situation. Today, half a billion human beings do not have latrines but they will be five billion in 2030. In addition to wars, lack of clean water is a powerful vector of diseases, causing three million deaths a year. Water is also essential to agriculture, since it takes between 800 and 4,000 liters for a kg of wheat. A kilo of beef requires between 2,000 and 16,000 liters.

The world population explains the lack of current climate change and its worsening in the coming decades. According to the UN demand to increase by 64 billion cubic meters per year. The solutions are clear policies for better sharing and use more careful. The makers probably discuss development assistance since, today, only 5% of these funds are intended to solve problems related to water supply.

We will have the opportunity to return to this thorny problem. On Sunday, March 22, closing day of the forum in Istanbul, is on Unesco’s World Water Day 2009.