Terremoto faz trilhos de trem entortarem

Em setembro, um terremoto chacoalhou Canterbury, na Nova Zelândia.


fonte:blog GeakAway

Vitória!

Entre muitos trabalhos, o meu aluno Diogo Farrapo Albuquerque, ganhou menção honrosa no ProIC, com o projeto "Estudo da Espessura Crustal Para as Estações da Rede Nacional do Observatório Sismológico".

Parabéns Diogo!

Parabéns ao Cesar Pavão, co-orientador! Obrigado Cesar!

"Embora a tempestade venha, um dia a chuva vai passar! Espero!"

Simpósio e Campo

O simpósio em Brasília foi um ShoW! Parabéns a equipe da organização.

Estou no campo fazendo a escolha de ponto para Linhares, Guarapari e Pico da Caledônia.

Apoio a RSIS, espero não levar mais um chute na ......

Essa rede vai ser um sucesso? Todos sismólogos brasileiros esperam.

Lista de Exercício na área.

alunos do curso de sismologia básica,

Observatório Sismológico registra tremor em Brasília

Prof. Mônica manda bem na sua entrevista!

Despedida da Juliane!

A nossa grande recepcionista saiu nessa quinta-feira para assumir a segurança do Metro. Muito sucesso para vc! Ju!

Humberto e suas palestras

Edivonete com a pipoca e a Prof. Mônica.

Ju comendo o seu bolinho! Eitá, Felicidade!

Humberto faz Jú chora com as palavras fortes!

Humberto tenta tomar novamente a vez da Jú! Mas a despedidada é da Jú.

Sidinei e Edivonete se afastam das palavras do Humberto.

Agora todos!

Fault maps could aid earthquake forecasts

fonte:Nature news 8/10/2010

Earth moved in the Chilean quake where the strain was highest.

Richard A. Lovett

A detailed analysis of Chile's February quake may help seisomologists to predict the severity of future termors. (LEO LA VALLE/epa/Corbis)

For 100 years, scientists have thought that earthquakes are caused by 'elastic rebound', in which strain builds up across fault lines until something causes the fault to slip in a big, earthquake-producing lurch. Only now — in the aftermath of the magnitude-8.8 earthquake that rocked Chile in February this year — have scientists been able to measure all of these events in action.

In a study in Nature¹, a team of geologists from the GFZ German Research Centre for Geosciences, Potsdam, compared earth movements during the Chilean earthquake to a decade's worth of measurements of strain build-up, finding that the greatest slippage indeed happened on parts of the fault that had accumulated the most strain.

The earthquake occurred on a section of the Andean subduction zone that represented a 'seismic gap' in which no major earthquake had occurred since 1835, when Charles Darwin reported one that is now thought to have had a magnitude of about 8.5.

Taking the strain

To determine how much strain had accumulated, the scientists used high-precision data from 232 Global Positioning System (GPS) stations spanning hundreds of kilometres of Chile, ranging from the Pacific coast to the Andes.

These instruments revealed, with millimetre precision, that this portion of Chile has been creeping eastwards at several centimetres per year. It has been forced in that direction by the Nazca plate under the Pacific Ocean, which is colliding with South America from the west.

Based on plate tectonics, the scientists knew how fast the two plates were converging, and by how much that would shove the South American plate eastwards if the two plates were not sliding past each other at all — or locked.

“The similarity is simply amazing.”

In some parts of the earthquake zone, they found, the ground had indeed been moving at precisely the rate consistent with the fault being locked in this way. Other areas, however, were moving more slowly, indicating that the fault was slowly slipping in those places. This slippage, they calculated, would have released part, but not all, of the accumulating strain.

The scientists next mapped the amount by which the ground lurched back (westwards) when the fault slipped, releasing the accumulated stress. Then they compared the amount of movement to the accumulated strain.

"The similarity is simply amazing," says Matthias Rosenau, a co-author on the current study. High-strain areas lurched by as much as 10 metres. Areas of low strain moved considerably less.

Prediction hopes

Although the earthquake rupture began in one of the high-stress regions, it didn't stop when it hit the nearest lower-strain (creeping) section of the fault. Rather, Rosenau says, it "bridged the gap", allowing hundreds of kilometres of accumulated strain to be released all at once.

When it did stop, he adds, it was at regions where the GPS data suggested that the fault was locked and presumably accumulating strain rapidly. But these regions weren't ripe for failure because they had seen relatively recent, large earthquakes: a magnitude-9.5 quake on one side of the fault in 1960, and one of magnitude 7.8 in 1985 on the other side. "It stopped in areas where stresses were relaxed by prior earthquakes," Rosenau says.

Although none of these findings is conceptually groundbreaking, other scientists still find them to be important because the Chilean quake provided a rare opportunity to measure precisely what happened before and after a 'great earthquake' — defined as magnitude-8 or bigger.

"There really are not a lot of examples of great earthquakes where we can document what actually happened as well as this," says Chris Goldfinger, head of the Active Tectonics and Seafloor Mapping Laboratory at Oregon State University, Corvallis. "You need a decade or so of dense GPS observations, and then you need a big earthquake. Then you need the earthquake to be very well recorded."

The study might also help scientists to come closer to forecasting earthquakes. "The study corroborates that the earthquake process, at least along plate boundaries, is not totally random," says Rosenau.

And, he adds, monitoring other faults with similar precision might allow scientists to track the build-up of stress along them. This would help to produce better estimates of the risk and severity of earthquakes, even if precise forecasts are not possible.

• References

  1. Moreno, M., Rosenau, M. & Oncken, O. Nature 467, 198-202 (2010).

Magnitude 7.7 - REGIÃO DE KEPULAUAN MENTAWAI, INDONESIA

Fonte:USGS
Alerta e ocorrência de Tsunami.

Magnitude	7.7
Dia-horário	Segunda, 25 de Outubro de 2010 à14:42:22 UTC Hora Local:21:42:22
Localização	3,484°S 100,114°E
Profundidade	20,6 km
Distancias	240 km W de Bengkulu, Sumatra, Indonesia 280 km S de Padang, Sumatra, Indonesia

Dado da estação SAML (Samuel, Brasil)

último registro

(Terça 26/10/2010 09:49 GMT)

Fonte dessa imagem: http://aslwww.cr.usgs.gov/Seismic_Data/telemetry_data/SAML_24hr.html

Observatório Sismológico na SNCT - até domingo 24/10

Com apoio do Sr. Excelência - Rômulo - Estamos indo bem, agradeço muito a você Rômulo pelo apoio.

Lucas, Rafaela, Rhayssa, Davi, Isadora e Rômulo
Rômulo explicando para os alunos

vídeo - sobre terremoto

Dados de satélite indicam verdadeira causa do terremoto no Haiti

Houve ruptura em múltiplas fissuras, e uma delas nem era conhecida. Descoberta do perfil real do tremor aponta para risco maior de novos abalos.

O terremoto de magnitude 7 que matou cerca de 200 mil haitianos no início deste ano não foi causado por deslocamento na falha geológica de Enriquillo-Plantain Garden, como os cientistas imaginavam. A verdadeira causa foi o colapso de múltiplas falhas, sendo que uma delas, mais profunda, nem era conhecida pelos geólogos.

As conclusões foram publicadas no site da revista especializada "Nature Geoscience". A falha de Enriquillo é a "fronteira" entre a placa tectônica do Caribe e a placa Norte-Americana.

A crosta da Terra é constituída por cerca de uma dúzia de grandes placas tectônicas (ou litosféricas), delimitadas por grandes falhas e profundas fossas oceânicas. O movimento da camada mais externa da Terra, mesmo que sejam só poucos centímetros por ano, produz tensões que vão se acumulando em vários pontos.

Os terremotos são efeitos desse processo geológico de acúmulo lento e liberação rápida de tensões entre as placas, quando as rochas atingem o limite de resistência e ocorre uma ruptura. O tamanho da área de ruptura, grande ou pequeno, determina se o evento será de menor intensidade (um mero abalo ou tremor de terra) ou um terremoto. Quanto maior a área de ruptura, maior a intensidade das vibrações emitidas.

Como o terremoto no Haiti, como agora se sabe, não envolveu deslizamento perto da superfície, mas na recém-descoberta "falha de Léogâne", mais profunda, o estudo sugere que o tremor não liberou toda a tensão geológica acumulada nos últimos dois séculos. Isso quer dizer que são muito prováveis outros terremotos com rupturas de superfície.

Os pesquisadores envolvidos no trabalho são do Laboratório de Propulsão a Jato (JPL, na sigla em inglês) da Nasa, da Agência de Pesquisas Geológicas dos Estados Unidos (USGS, na sigla em inglês), do Instituto de Tecnologia da Califórnia em Pasadena, da Universidade do Texas em Austin e da Universidade de Nagoya (Japão). Eles utilizaram uma combinação de observações sismológicas, dados geológicos colhidos em campo e medidas obtidas por satélite para analisar a fonte do terremoto.

fonte:G1(14/10)

Veja o vídeo publicado antes no blog!

Limite Tocantins-Goias - Região de Mara Rosa

Magnitude 5.0 mb, 4.6 mR
2010-10-08 20:16:54.5 UTC --> 17:16:45 hora local
localização: 13.86 S ; 49.24 W
Profundidade: 2 km??
Distancia: 48 km S Porangatu (pop 32,758 ; local time 18:16 2010-10-08

How Rainfall Variation Can Trigger Earthquakes

Fonte: ScienceDaily 5 October 2010.

ScienceDaily (Oct. 5, 2010) — A new review article explores natural crustal earthquakes associated with the elements of the hydrologic cycle, which describes the continuous movement of water on, above and below the surface of the Earth, including hurricanes and typhoons. The theory of hydroseismicity, first articulated in 1987, attributes most intraplate and near-intraplate earthquakes, to the dynamics of the hydrological cycle.

The Hydroseismicity hypothesis suggests variations in rainfall affect pore-fluid pressure at depth and can trigger earthquakes in areas already under stress and near failure. This report cites documentation of metrological events -- rainfall, stream flow, hurricanes -- and observed seismic activity by more than 20 research teams across five continents, providing thorough testing and support of the Hydroseismicity hypothesis.

The authors suggest that the reported correlations between meteorological events and seismicity indicate the need for more local and regional earthquake monitoring networks as well as additional stream gauging stations. In the future it should be possible to discover and quantify causal relationships between earthquakes and meteorological parameters when better focal depths and more stream gauging stations become available. Groundwater hydrology measurements and earthquake monitoring and forecasting might eventually complement each other.

30 anos da série Cosmos! Uma homenagem ao grande divulgador da ciência: Carl Sagan.

“Nós somos uma forma do Cosmos conhecer a si mesmo”.

Série Cosmos - Youtube

Haiti earthquake: It wasn't the fault of Enriquillo

Sismólogos do Brasil - Tem concurso na UFRN

Desde do dia 20/09 está aberto concurso da UFRN. Vai até o dia 22/10!

É uma cidade fantástica
É um excelente grupo de sismologia
Quem passar nesse concurso estará bem nos próximos 30 anos! Projeto com a Petrobras está execução!!!

Abraços
George Sand França

Tremor em Mara Rosa - 3.5

Mas notícias será dada pelo o Observatório Sismológico
Veja no site do SIS

GO: tremor de 3,5 graus de magnitude é sentido em 5 cidades

Terra Brasil - 49 minutos atrás

Além disso, o epicentro do tremor foi afastado das cidades. Mara Rosa foi o município mais atingido, segundo os registros feitos pelo observatório. ...

A diferença é que nessa região não dá na forma de enxame!

Abraços

Do Blog Além da Chuva!

Muito boa a idéia do pulo!!!

Fonte: clique aqui

4.9 na Acre - Profundo - pouco provável causar danos

Magnitude	4.9
Dia-horário	Quinta, 20 de setembro de 2010 as 23:30:46 UTC
Localização	7,924°S, 71,306°W
Profundo	630.8 km
Region	AMAZONAS, BRASIL
Distances	145 km ESE de Cruzeiro do Sul, Acre. 435 km SSW de Tabatinga, Amazonas.

Dados da estação de SAML (Samuel, Brasil)

Sexta10/01/10 16:48 GMT - Vc consegue ver o evento.

100% Chance of an Earthquake

100% Chance of an Earthquake

There's a 100 percent chance of an earthquake today. Though millions of persons may never experience an earthquake, they are very common occurrences on this planet. So today -- somewhere -- an earthquake will occur.

It may be so light that only sensitive instruments will perceive its motion; it may shake houses, rattle windows, and displace small objects; or it may be sufficiently strong to cause property damage, death, and injury.

It is estimated that about 700 shocks each year have this capability when centered in a populated area. But fortunately, most of these potentially destructive earthquakes center in unpopulated areas far from civilization.

Since a major portion of the world's earthquakes each year center around the rim of the Pacific Ocean (Ring of Fire), referred to by seismologists as the circum-Pacific belt, this is the most probable location for today's earthquake. But it could hit any location, because no region is entirely free of earthquakes.

Stating that an earthquake is going to occur today is not really "predicting earthquakes". To date, they cannot be predicted. But anyone, on any day, could make this statement and it would be true. This is because several million earthquakes occur annually; thereby, thousands occur each day, although most are too small to be located. The problem, however, is in pinpointing the area where a strong shock will center and when it will occur.

Earthquake prediction is a future possibility, though. Just as the Weather Bureau now predicts hurricanes, tornadoes, and other severe storms, the NEIC may one day issue forecasts on earthquakes. Earthquake research was stepped up after the Alaska shock in 1964. Today, research is being conducted by the USGS and other federal and state agencies, as well as universities and private institutions. Earthquake prediction may some day become a reality, but only after much more is learned about the earthquake mechanism.