terça-feira, 30 de setembro de 2008
quinta-feira, 25 de setembro de 2008
From The Economist print edition
How to use your laptop to locate an earthquake
IF YOU drop your laptop computer, a chip built into it will sense the acceleration and protect the delicate moving parts of its hard disk before it hits the ground. A group of researchers led by Jesse Lawrence of Stanford University are putting the same accelerometer chip to an intriguing new use: detecting earthquakes. They plan to create a network of volunteer laptops that can map out future quakes in far greater detail than traditional seismometers manage.
Seismometers are large, expensive beasts, costing $10,000 or more apiece. They are designed to be exquisitely sensitive to the sort of vibrations an earthquake produces, which means they can pick up tremors that began halfway around the world. By contrast, the accelerometer chips in laptops, which have evolved from those used to detect when a car is in a collision and thus trigger the release of the airbags, are rather crude devices. They are, however, ubiquitous. Almost all modern laptops have them and they are even finding their way into mobile phones. The iPhone, for example, uses such a chip to detect its orientation so that it can rotate its display and thus make it easily readable.
On its own, an accelerometer chip in a laptop is not very useful for earthquake-detection, as it cannot distinguish between a quake and all sorts of other vibrations—the user tapping away at the keyboard, for example. But if lots of these chips are connected to a central server via the internet, their responses can be compared. And if a large number in a particular place register a vibration at almost the same time, it is more likely to be an earthquake than a bunch of users all hitting their space bars. To exploit this group effect, Dr Lawrence’s Quake-Catcher Network (QCN) employs the same software that is used by the SETI@home project, which aggregates computing power from hundreds of thousands of volunteer computers around the world to analyse radio-telescope signals for signs of extraterrestrial intelligence.
Dr Lawrence and his colleagues have already demonstrated that the QCN works. It detected a quake near Reno, Nevada, in April, and one near Los Angeles in July. Merely detecting a quake, however, is not the point. Seismometers can do that. To be useful, the QCN needs to be able to do things that seismometers cannot.
One of those things is to measure the maximum amount of ground shaking. The sensitivity of seismometers means that strong signals would damage them if they were not designed to “clip” such signals when they exceed a certain threshold. The price paid is that information about strong, nearby earthquakes is lost. Laptop accelerometers are more robust. Though they cannot, if in America, tell you anything about an earthquake in China, they can sometimes do better than conventional kit when measuring local quakes.
The network’s second benefit is of sheer numbers. This should allow the construction of far more detailed maps of the up-and-down and side-to-side motions induced by earthquakes. These vary a lot from quake to quake, and that means the damage done by a quake of any given strength is also variable. A better understanding of how movement and damage relate might help both building design and town planning in earthquake zones.
Of course, for that to work, you have to know where each laptop was at the moment of the quake. Ideally, this information would come from a Global Positioning System device fitted within the laptop, but few computers have them at the moment. In their absence, information automatically supplied about the site of the nearest router (a network device that computers use to connect to the wider internet) gives a rough location. This is imperfect, but pooling the data from lots of laptops means that location errors can be detected statistically and erroneous data discarded.
If that can be done quickly enough, the QCN could bring a third—and most valuable—benefit: warning. The speed of internet communication, coupled with a scheme for uploading data from each computer at brief intervals, means that Dr Lawrence’s network could issue an earthquake warning within seconds. That is faster than traditional seismometer networks, which update less regularly, and, above all, is much faster than seismic waves travel. Warnings could thus be broadcast to places the earthquake waves had not yet reached, giving people vital time to find a place of refuge.
At the moment, the QCN has about 1,500 participating computers. But, as happened with SETI@home, the researchers expect numbers to grow once knowledge of the project spreads: qcn.stanford.edu, for those who want to join in the fun.
domingo, 21 de setembro de 2008
Horário 20 de Setembro de 2008 às 14:43:05 UTC
Profundidade 41.5 km valor fixo
160 km SSE of Puquio, Peru
240 km W of Arequipa, Peru
Dados da Estação RCBR (Riachuelo, Brasil)
último registro às 05:48 21/09/08 GMT
sábado, 20 de setembro de 2008
Earthquakes and Animals
Across Southern California, the 5.4 earthquake rattled furry nerves and ruffled feathers--literally.
"My birds felt it first," reported one reader. "They were all fluffy and upset a few seconds before it happened."
In Chino Hills, the epicenter of the quake, Alissa Sissung's 10-year-old daughter, Delaney, was spending the day at a horse camp not far from her home. Just before the ground began to quiver, her daughter watched the horses and dogs stir nervously, Sissung told Times reporter Molly Hennessy-Fiske.
Another reader e-mailed: "I was feeding my horse when all of a sudden, he took off running. Seconds later is when the earthquake hit."
And word filtered in to us from Garden Grove about a greyhound at a rescue shelter who rarely gets up, but who suddenly stood up and looked around, to the surprise of the humans there. Then the earthquake hit.
Whether they really could sense the earthquake a'coming--as fabled--or were as jolted into surprise as their people, the area's animals seem to have withstood the temblor as well as humans did.
Although, like people, they did their share of freaking out. "My cats went running through the room scared to death," Michael Gelfond, an attorney working out of his Beverlywood home office, told Times reporter Tami Abdollah.
Elizabeth Gonzales suffered one of the day's few quake-related injuries--a dog bite. The veterinarian was examining a mixed-breed terrier when the walls of Chino Hills Small Animal Hospital began to rattle. The frightened dog promptly sunk its teeth into Gonzales' hand.
"They are pretty deep punctures," Gozales told L.A. Times reporter Paul Pringle. But "he's always been a good doggie."
Gonzales says that reaction is not unusual. Dogs, cats, and other animals often become terrified when the ground moves. "They don't know what's going on," she said. "They don't feel secure in their surroundings." Gonzales advises keeping dogs and cats away from windows during and immediately after a quake, lest they jump out in panic. "Their first instinct is, 'Where can I go hide?'"
The Los Angeles county shelter system reported that all its animals and buildings weathered the quake just fine. Same report from the Los Angeles city shelters. "No damage," said L.A. Animal Services general manager Ed Boks. "And, no, the animals did not give us any warning of the earthquake--like they're supposed to," he deadpanned.
Even in Pomona, just seven miles from the epicenter, the Inland Valley Humane Society survived undamaged, and the animals were well, according to Jim Edward, operations manager of the shelter. "You hear so many stories about how they're intuitive and seem to know it's coming," Edward said. "No. It was just another day for them. Maybe it's the soft music we play in the kennels."
fonte:Los Angeles Times
PETS MAY BE ABLE TO PREDICT EARTHQUAKES
“They’re on the ground in bare feet and they can feel these things. Their senses are so much more alive than ours,” Hettig said Thursday.
Others said their pets were scared by the quake.
"I have a yellow-headed Amazon and when there's an earthquake he flutters down to the bottom of his cage and acts like he's being attacked, but he doesn't know by what," said Cindy Scott, a vet tech at Animal Emergency Clinic of the Desert.
What are some tips to keep your pets safe in case of an earthquake?
-Make sure there is a supply of canned/dry pet food and bottled water with other emergency supplies including pet prescription and medicine.
-If roads are blocked because of a natural disaster, professional help may not be immediately available so familiarize yourself and other family members with pet CPR, resuscitation and general first aid procedures. Your quick action can save your pet's life.
-Try not to display stress or anxiety when dealing with pets. Most animals are very aware of their owner's emotions and can read your stress. This can cause otherwise calm pets to display aggressive behavior.
-After a fire or disaster, check pet structures and favorite hiding places for hazardous debris.
-Ask your local fire department, animal shelter, or veterinarian for a "Pet Alert" sign for doors and windows. In non are available, make your own by listing your pets on a 3 by 5 card and display it prominently. This alerts emergency teams there may be pets that need assistance.
-Dogs and cats should wear I.D. tags with current address and/or phone numbers at all times. This will make it easier for you and your pet to be reunited if separated.
-Keep up-to-date on your pet's vaccinations. Pets may become disoriented and stray, or housed in shelters with other animals herby potentially becoming exposed to infectious diseases.
-Alert local shelters if your pet is missing.
terça-feira, 16 de setembro de 2008
Horário 16 de Setembro às 07:28:25 UTC
Localização 0.958°N, 29.010°W
Profundiade 10 km Valor fixo
650 km NE de Fernando de Noronha, Pernambuco, Brasil
1020 km NE de Natal, Rio Grande do Norte, Brasil
1185 km NNE de Recife, Pernambuco, Brasil
Dados da estação RCBR (Riachuelo, Brasil)
último registro 17/09/08 00:18 GMT
quinta-feira, 11 de setembro de 2008
Data: 11 setembro de 2008
Hora de origem: 12:35:26,7 (UTC) (tabela Jeffreys & Bullet, 1967)
Hora FOR1: 12:35:57,7 (UTC)
Epicentro: Meruoca-Sobral-Alcântaras (CE)
Lat.: -03,62º - Long.: -40,53º (Erro: ± 10 km) - Prof. 3 km (fixa)
S-P (FOR1): 22,3 seg. - Dist.: 190,4 km (1,7º)
Vp: 0,27 micr/seg.
quarta-feira, 10 de setembro de 2008
|Profundidade||10 km (Valor fixo por programa|
|Distancias||1260 km NNE de Parnaiba, Piaui, Brasil|
1320 km NNE de São Luis, Maranhao, Brasil
sábado, 6 de setembro de 2008
Essa atividade é para obter o certificado de Sismólogo.
baixar aqui o procedimento em Português
quinta-feira, 4 de setembro de 2008
Horário 03/09/2008 ás 11:25:13 GMT
Localização 26.569°S, 63.181°W
DProfundidade 547.4 km
EM SANTIAGO DEL ESTERO, ARGENTINA
170 km NE de Santiago del Estero, Argentina
último registro as 02:48 GMT 04/09/08
quarta-feira, 3 de setembro de 2008
Da Secretaria de Comunicação da UnB
Ilustração Marcelo Jatobá/UnB Agência
A previsão é que sejam realizados 18 tiros, separados 50 km um do outro, carregados com até duas toneladas de um produto semelhante à dinamite. Segundo o professor do Instituto de Geociências (IG) da UnB Reinhardt Adolfo Fuck, o cálculo para descobrir a espessura leva em consideração a velocidade com que as ondas causadas pelas explosões controladas percorrem a crosta terrestre. “Varia de acordo com a densidade e a estrutura da rocha”, explica.
Outra etapa adiantada é a das investigações gravimétricas, que analisa as propriedades da rocha pelas variações na aceleração da gravidade e “pode oferecer informações preciosas sobre a variação da natureza das rochas”.