A erupção pliniana do Pinatubo, que afetou significativamente o clima da Terra, começou há 35 anos

The eruption column of Mount Pinatubo on June 12, 1991, three days before the climactic eruption

      

Mount Pinatubo is an active stratovolcano located on the island of Luzon, near the tripoint of the Philippine provinces of Zambales, Tarlac, and Pampanga. It is located in the Cabusilan Mountains separating the west coast of Luzon from the central plains. Before the volcanic activities of 1991, its eruptive history was unknown to most people. It was heavily eroded, inconspicuous and obscured from view. It was covered with dense forest which supported a population of several thousand indigenous people, the Aetas, who fled to the mountains during the Spanish conquest of the Philippines.

The volcano's Plinian/Ultra-Plinian eruption on June 15, 1991, produced the second largest terrestrial eruption of the 20th century after the 1912 eruption of Novarupta in the Alaska Peninsula. Complicating the eruption was the arrival of Typhoon Yunya bringing a lethal mix of ash and rain. Successful predictions at the onset of the climactic eruption led to the evacuation of tens of thousands of people from the surrounding areas, saving many lives, but the surrounding areas were severely damaged by pyroclastic flows, ash deposits, and subsequently, by the lahars caused by rainwaters re-mobilizing earlier volcanic deposits causing extensive destruction to infrastructure and altering the river systems months to years after the eruption.

The effects of the eruption were felt worldwide. It ejected roughly 10,000,000,000 tonnes  or 10 km³ of magma, and 20,000,000 tonnes of SO2, bringing vast quantities of minerals and metals to the surface environment. It injected large amounts of particulate into the stratosphere – more than any eruption since that of Krakatoa in 1883. Over the following months, the aerosols formed a global layer of sulfuric acid haze. Global temperatures dropped by about 0.5 °C and ozone depletion temporarily increased substantially.

   

       

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Nunca vos esqueceremos, Maurice e Katia...

Os vulcanólogos Katia e Maurice Kraft morreram na erupção do Unzen há 35 anos...

   

Katia Krafft (Mulhouse, 17 April 1942 – Unzen, 3 June 1991) and her husband, Maurice Krafft (Guebwiller, 25 March 1946 – Unzen, 3 June 1991) were French volcanologists who died in a pyroclastic flow on Mount Unzen, in Japan, on June 3, 1991. Their obituary appeared in the Bulletin of Volcanology, (vol. 54, pp 613–614).

Maurice and Katia were known for being pioneers in filming, photographing and recording volcanoes, often getting within feet of lava flows. They met at Strasbourg University, and their career as volcano observers began soon after. With little money, they saved up for a trip to Stromboli and photographed the eruption. Finding that people were interested in this documentation of eruptions, they soon made a career out of this, which afforded them the ability to travel the globe.

The Kraffts were often the first to arrive at an active volcano, and were respected and envied by many volcanologists. Their footage of the effects of volcanic eruptions was a considerable factor in gaining the cooperation of local authorities faced with volcanic threats. One notable example of this was after the onset of activity at Mount Pinatubo in 1991, where their video of the effects of the eruption of Nevado del Ruiz in Colombia was shown to large numbers of people, including Philippine President Cory Aquino, and convinced many skeptics that evacuation of the area would be necessary.

In June 1991, while filming eruptions at Mount Unzen, they were caught in a pyroclastic flow which unexpectedly swept out of a channel others had been flowing down and onto the ridge they were standing on. They were killed instantly, along with 40 journalists also covering the eruptions.

The work of the Kraffts was highlighted in a video issue of National Geographic, which contained a large amount of their film footage and photographs as well as interviews with both. Maurice is famous for saying in the video that "I am never afraid because I have seen so much eruptions in 23 years that even if I die tomorrow, I don't care," coincidentally on the day before his death. Volcano: Nature's Inferno. [videorecording]. Washington, DC: National Geographic Society. 2003.

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O vulcanólogo David A. Johnston morreu há 46 anos: Vancouver! Vancouver! This is it!

The last picture ever taken of Johnston, 13 hours before his death at the eruption site

 

David Alexander Johnston (Chicago, December 18, 1949 – Mount St. Helens, May 18, 1980) was an American United States Geological Survey (USGS) volcanologist who was killed by the 1980 eruption of Mount St. Helens in the U.S. state of Washington. A principal scientist on the USGS monitoring team, Johnston was killed in the eruption while manning an observation post six miles (10 km) away on the morning of May 18, 1980. He was the first to report the eruption, transmitting "Vancouver! Vancouver! This is it!" before he was swept away by a lateral blast; despite a thorough search, Johnston's body was never found, but state highway workers discovered remnants of his USGS trailer in 1993.

Johnston's career took him across the United States, where he studied the Augustine Volcano in Alaska, the San Juan volcanic field in Colorado, and long-extinct volcanoes in Michigan. Johnston was a meticulous and talented scientist, known for his analyses of volcanic gases and their relationship to eruptions. This, along with his enthusiasm and positive attitude, made him liked and respected by many co-workers. After his death, other scientists lauded his character, both verbally and in dedications and letters. Johnston felt scientists must do what is necessary, including taking risks, to help protect the public from natural disasters. His work, and that of fellow USGS scientists, convinced authorities to close Mount St. Helens to the public before the 1980 eruption. They maintained the closure despite heavy pressure to re-open the area; their work saved thousands of lives. His story became intertwined with the popular image of volcanic eruptions and their threat to society, and a part of volcanology's history. To date, Johnston, along with his mentee Harry Glicken, is one of two American volcanologists known to have died in a volcanic eruption.

Following his death, Johnston was commemorated in several ways, including a memorial fund established in his name at the University of Washington to fund graduate-level research. Two volcano observatories were established and named after him: one in Vancouver, Washington, and another on the ridge where he died. Johnston's life and death are featured in several documentaries, films, docudramas and books. A biography of his life, A Hero on Mount St. Helens: The Life and Legacy of David A. Johnston, was published 2019.

 

 

 Johnston using a correlation spectrometer, which measures ultraviolet radiation as an indicator of the sulfur dioxide content of gases ejected from Mount St. Helens (photographed on April 4, 1980)

 

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O vulcão do Monte Santa Helena teve forte erupção há 46 anos...

  

O Monte Santa Helena (em inglês Mount St. Helens) é um vulcão ativo que fica no sudoeste do estado norte-americano de Washington, 154 quilómetros a sul de Seattle e a 80 a nordeste de Portland.

Após 127 anos de inatividade o vulcão entrou violentamente em erupção no dia 18 de maio de 1980, às 08.32 horas, locais (hora do Pacífico), matando 57 pessoas e ferindo muitas outras.

Após um tremor de terra de magnitude 5,1 na escala de Richter, o lado norte do monte entrou em violenta erupção, provocando danos ambientais numa área de 550 km². A cinza emanada da erupção provocou problemas respiratórios nos habitantes até 1.550 quilómetros de distância do vulcão.

Como resultado da explosão a altura da cratera do vulcão diminuiu cerca de 400 metros, passando de 2.950 para 2.549 metros, e teve a sua largura aumentada de cerca de dois quilómetros.

  

Tectónica de Placas dos vulcões da Cordilheira das Cascatas

   

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In 1980, a major volcanic eruption occurred at Mount St. Helens, a volcano located in Washington, in the United States. The eruption (which was a VEI 5 event) was the only significant one to occur in the contiguous 48 US states since the 1915 eruption of Lassen Peak in California. The eruption was preceded by a two-month series of earthquakes and steam-venting episodes, caused by an injection of magma at shallow depth below the volcano that created a huge bulge and a fracture system on Mount St. Helens' north slope.
Prior to the eruption, USGS scientists convinced local authorities to close Mount St. Helens to the general public and to maintain the closure in spite of pressure to re-open it; their work saved thousands of lives. An earthquake at 8:32:17 a.m. PDT (UTC−7) on Sunday, May 18, 1980, caused the entire weakened north face to slide away, suddenly exposing the partly molten, gas- and steam-rich rock in the volcano to lower pressure. The rock responded by exploding a hot mix of lava and pulverized older rock toward Spirit Lake so fast that it overtook the avalanching north face.
An eruption column rose 80,000 feet (24,400 m) into the atmosphere and deposited ash in 11 U.S. states. At the same time, snow, ice and several entire glaciers on the volcano melted, forming a series of large lahars (volcanic mudslides) that reached as far as the Columbia River, nearly 50 miles (80 km) to the southwest. Less severe outbursts continued into the next day only to be followed by other large but not as destructive eruptions later in 1980.
Fifty-seven people (including innkeeper Harry R. Truman, photographer Reid Blackburn and geologist David A. Johnston) perished. Hundreds of square miles were reduced to wasteland causing over a billion U.S. dollars in damage ($2.74 billion in 2011 dollars), thousands of game animals killed, and Mount St. Helens was left with a crater on its north side. At the time of the eruption, the summit of the volcano was owned by the Burlington Northern Railroad, but afterward the land passed to the United States Forest Service. The area was later preserved, as it was, in the Mount St. Helens National Volcanic Monument.

   

    

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O vulcão Eyjafjallajökull arrasou a aviação comercial há dezasseis anos...

Pluma vulcânica durante a segunda erupção, em 18 de abril de 2010.

 

As erupções ocorridas em 2010 no glaciar Eyjafjallajökull foram uma série de grandes eventos vulcânicos que ocorreram em Eyjafjallajökull na Islândia. A atividade sísmica, que se iniciou no final de 2009, deu lugar a uma erupção vulcânica que começou a 20 de março de 2010, colocando o seu Índice de Explosividade Vulcânica em 1. Uma fase da erupção, a 14 de abril de 2010, causou uma paralisação generalizada do transporte aéreo europeu, afetando milhares de voos e causando uma espécie de efeito dominó em todo o mundo.

   

   
Em outubro de 2010 as erupções cessaram, segundo declarações de Ármann Höskuldsson, cientista do Instituto de Ciências Terrestres da Islândia, embora a área ainda esteja geotermicamente ativa e ainda haja uma possibilidade de novas erupções no futuro.

 

Mapa com a nuvem de cinza vulcânica abrangendo nos dias de 14 a 25 de abril de 2010

 

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O vulcão Paricutín nasceu há oitenta e três anos...!

O Paricutín é um vulcão muito recente situado no estado de Michoacán, no México, (19°29'35.70"N, 102°15'3.93"O), entre as povoações de San Juan Parangaricutiro (El nuevo) e Angahuan. Está incluído em algumas listas das sete maravilhas naturais do mundo. A cidade mais próxima deste vulcão é Uruapan.

A maior parte do desenvolvimento deste vulcão ocorreu durante o seu primeiro ano de existência (1943), enquanto se encontrava na sua fase piroclástica explosiva. Durante diversas semanas desse ano, um grande número de ruídos estranhos foram ouvidos pelos habitantes em torno da pequena aldeia de Paricutín, apesar das condições meteorológicas serem normais.
   

O vulcão Paricutín no início da sua atividade

    
O primeiro ano do vulcão

A atividade sísmica intensificou-se a 20 de fevereiro de 1943, quando o agricultor Dioniso Pulido testemunhou a abertura de uma fissura vulcânica no meio do seu campo de milho. De acordo com alguns testemunhos, os aldeões tentaram fechar as fissuras enchendo-as com as rochas e o solo, antes que pequenas explosões e tremores violentos começassem a agitar a área. Os residentes das aldeias próximas fugiram e, 24 horas após o aparecimento da fissura inicial, o vulcão já tinha construído um cone com 50 metros de altura. No espaço de uma semana esta altura tinha já duplicado.

No mês de março seguinte, a atividade do vulcão intensificou-se, ejetando a cinza no ar em colunas de vários quilómetros de altura e começando a avançar sobre as povoações de Paricutín e de San Juan (conhecida também como San Juan Parangaricutiro). Em 12 de junho, um grande fluxo de lava tinha começado a atingir Paricutín, que foi evacuada no dia seguinte. San Juan seria evacuada meses mais tarde, e por agosto desse ano, ambas as localidades tinham sido abandonadas, soterradas, em grande parte, por lava e cinza.
   

Vestígios da velha povoação de San Juan Parangaricutiro na atualidade

     
Diminuição de atividade

Muito do crescimento do vulcão ocorreu durante o primeiro ano, quando se encontrava ainda na fase piroclástica explosiva. No fim desta fase, após aproximadamente um ano, o vulcão tinha crescido até aos 336 metros de altura. Nos oito anos seguintes o vulcão continuaria em erupção, embora este período fosse dominado por erupções relativamente ligeiras de lava, que chamuscariam os 25 quilómetros quadrados em torno. A atividade do vulcão declinaria lentamente durante este período até os últimos seis meses da erupção, durante a qual a atividade violenta e explosiva foi frequente. Em 1952, a erupção terminou, e o Paricutín parou de crescer, alcançando uma altura final de 424 metros acima do terreno em que "nasceu" (elevação de 3170 metros acima do nível do mar, uma vez que se situa num plateau vulcânico elevado). Como a maioria dos cones de cinza, o Paricutín é um vulcão monogenético, o que significa que nunca voltará a ocorrer uma erupção.

O Paricutín é um dos dois vulcões que se sabe terem sido formados na história recente. O outro, cujo aparecimento ocorreu aproximadamente 183 anos antes, é conhecido como El Jorullo. O Paricutín e o El Jorullo são as formações vulcânicas mais recentes do campo vulcânico de Michoacán - Guanajuato, que é pontilhado com muitos cones de cinza, fluxos de lava, pequenos vulcões, abóbadas de lava e maars.

O vulcanismo é um aspeto comum na paisagem mexicana. O Paricutín é meramente o mais novo dos mais de 1.400 respiradouros vulcânicos que existem na cadeia vulcânica Trans-Mexicana, que se estende pela região que inclui Michoacán e Guanajuato. Este vulcão é original pelo facto de que a sua formação foi testemunhada desde o início. Surpreendentemente, nenhuma morte foi causada pela erupção, embora três pessoas tenham morrido em consequência de relâmpagos associados à erupção.

   

         

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Há 212 anos uma erupção do vulcão Mayon matou cerca de mil e duzentas pessoas...

Fotografia das ruínas de Cagsawa com os restos da igreja ainda em pé, destruída em durante a erupção de 1814

O vulcão Mayon é um vulcão nas Filipinas, situado na província de Albay (Bicol). O seu cume com a forma de um cone quase perfeito é considerado como sendo ainda mais belo do que o Monte Fuji, no Japão. Alguns quilómetros a sul do vulcão situa-se a cidade de Legazpi.

O Mayon é classificado por vulcanólogos como um estratovulcão (vulcão composto). O seu cone simétrico foi formado alternadamente por fluxos piroclásticos e escoadas de lava. É o vulcão mais ativo do país, tendo entrado em erupção pelo menos 50 vezes nos últimos 400 anos.

A erupção mais destrutiva do Mayon, alvo de relatos ou registos, ocorreu a 1 de fevereiro de 1814, tendo os fluxos de lava enterrado na cidade de Cagsawa e cerca de 1200 pessoas pereceram, tendo apenas resistido o campanário da igreja.
  

Principais vulcões filipinos

    

Situa-se entre a Placa Euroasiática e a Placa Filipina, numa fronteira com potencial altamente destrutivo, pois a placa continental, ao ser empurrada por uma placa oceânica, esta última, que é mais densa, é obrigada a descer, o que provoca a formação de magma no plano de Benioff assim gerado.

A sua última erupção foi em 2009.

   

Fluxos piroclásticos descem através das encostas do vulcão, em 1984

        

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Há quatro anos terminou a erupção nas Canárias...

La erupción volcánica de La Palma de 2021 se inició el 19 de septiembre en la zona de Montaña Rajada,​ cercano a la localidad de El Paraíso del municipio de El Paso, en la isla de La Palma, perteneciente al archipiélago atlántico de Canarias (España).​ Fue la última erupción en la isla desde la del Teneguía en 1971 y la última en Canarias desde la submarina de El Hierro de 2011.​ La erupción del volcán de Tajogaite se detuvo el 13 de diciembre tras 85 días de actividad,​ siendo la erupción histórica más larga registrada en la isla y tercera en el archipiélago, tras Timanfaya en Lanzarote y Tagoro en El Hierro.​ El 19 de diciembre de 2023 se anunció en el BOC las medidas cautelares por la posible existencia de valores geomorfológicos, por lo que quedarían protegido el volcán de Tajogaite y su entorno, así como las dos fajanas.​ El 9 de febrero de 2023 el Cabildo de La Palma oficializó en sesión plenaria la denominación de Volcán de Tajogaite para esta erupción.

 

Extensión de la colada de lava con resaltado de edificios destruidos, el 23 de noviembre de 2021

 

19 de septiembre

Después de más de 25.000 pequeños terremotos que azotaron la isla durante ocho días, a las 15:10 (hora local)​ se inició la erupción en un paraje denominado Cabeza de Vaca, en el lugar de Las Manchas, municipio de El Paso.​ La erupción tenía inicialmente dos fisuras separadas por 200 metros, y ocho bocas.​ Autoridades como la Guardia Civil, que desplegó sobre el terreno a más de 120 efectivos, estimaron que el número total de evacuados podría superar los 10 000, consonante al recorrido que hiciese la lava hacia la costa. Igualmente y en prevención de que la lava cortase las carreteras de acceso a los núcleos costeros, se evacuó Puerto Naos, La Bombilla, El Remo y Charco Verde, que hubieran quedado incomunicados. También se cerraron al tráfico varias carreteras por prevención.

 

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O vulcanólogo David A. Johnston nasceu há 76 anos...

The last picture ever taken of Johnston, 13 hours before his death at the eruption site

 

David Alexander Johnston (Chicago, December 18, 1949 – Mount St. Helens, May 18, 1980) was an American United States Geological Survey (USGS) volcanologist who was killed by the 1980 eruption of Mount St. Helens in the U.S. state of Washington. A principal scientist on the USGS monitoring team, Johnston was killed in the eruption while manning an observation post six miles (10 km) away on the morning of May 18, 1980. He was the first to report the eruption, transmitting "Vancouver! Vancouver! This is it!" before he was swept away by a lateral blast; despite a thorough search, Johnston's body was never found, but state highway workers discovered remnants of his USGS trailer in 1993.

Johnston's career took him across the United States, where he studied the Augustine Volcano in Alaska, the San Juan volcanic field in Colorado, and long-extinct volcanoes in Michigan. Johnston was a meticulous and talented scientist, known for his analyses of volcanic gases and their relationship to eruptions. This, along with his enthusiasm and positive attitude, made him liked and respected by many co-workers. After his death, other scientists lauded his character, both verbally and in dedications and letters. Johnston felt scientists must do what is necessary, including taking risks, to help protect the public from natural disasters. His work, and that of fellow USGS scientists, convinced authorities to close Mount St. Helens to the public before the 1980 eruption. They maintained the closure despite heavy pressure to re-open the area; their work saved thousands of lives. His story became intertwined with the popular image of volcanic eruptions and their threat to society, and a part of volcanology's history. To date, Johnston, along with his mentee Harry Glicken, is one of two American volcanologists known to have died in a volcanic eruption.

Following his death, Johnston was commemorated in several ways, including a memorial fund established in his name at the University of Washington to fund graduate-level research. Two volcano observatories were established and named after him: one in Vancouver, Washington, and another on the ridge where he died. Johnston's life and death are featured in several documentaries, films, docudramas and books. A biography of his life, A Hero on Mount St. Helens: The Life and Legacy of David A. Johnston, was published 2019.

 

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Há 64 anos uma erupção vulcânica provocou a evacuação da ilha de Tristão da Cunha...

   

Em agosto e setembro de 1961 a ilha de Tristão da Cunha teve a única erupção histórica desde que a ilha começou a ser habitada, no século XIX.

Assim, em 10 de outubro de 1961 os seus habitantes decidiram abandonar a sua ilha (mais exatamente a sua única localidade, Edimburgo dos Sete Mares, assim chamada em homenagem ao Duque de Edimburgo, o príncipe Alfredo, segundo filho da Rainha Victoria, que visitou a ilha em 1867), partindo nos barcos pesqueiros até serem recolhido por um barco que ia buscar alunos para o Reino Unido e que acabou por levar os cerca de 300 habitantes para a Cidade do Cabo (e daqui foram levados para o Reino Unido).

Depois da erupção terminar, em 1962, o governo do Reino Unido não queria que eles regressassem, mas os insulares resolveram voltar e recomeçar a sua vida na ilha, após votação democrática, em 1963.

Hoje tem uma população de cerca de 251 cidadãos britânicos, orgulhosos de viveram na ilha mais inacessível da Terra (nisto rivalizam com Pitcairn, pois não têm aeroporto e/ou televisão - e a ilha ou cidade mais próximas são a ilha de Santa Helena, 2.420 km a norte, e estão a 2.800 km da Cidade do Cabo, a leste).

Vivem agora, na única ilha habitada do arquipélago, cerca de oitenta famílias, que se dedicam à pesca, agricultura e venda dos selos da ilha, num estilo de vida único...

     

 
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Selos comemorativos da erupção e evacuação de dos habitantes de Tristão da Cunha, em outubro de 1961

Há quatro anos começou uma erupção nas Canárias...

La erupción volcánica de La Palma de 2021 se inició el 19 de septiembre en la zona de Montaña Rajada,​ cercano a la localidad de El Paraíso del municipio de El Paso, en la isla de La Palma, perteneciente al archipiélago atlántico de Canarias (España).​ Fue la última erupción en la isla desde la del Teneguía en 1971 y la última en Canarias desde la submarina de El Hierro de 2011.​ La erupción del volcán de Tajogaite se detuvo el 13 de diciembre tras 85 días de actividad,​ siendo la erupción histórica más larga registrada en la isla y tercera en el archipiélago, tras Timanfaya en Lanzarote y Tagoro en El Hierro.​ El 19 de diciembre de 2023 se anunció en el BOC las medidas cautelares por la posible existencia de valores geomorfológicos, por lo que quedarían protegido el volcán de Tajogaite y su entorno, así como las dos fajanas.​ El 9 de febrero de 2023 el Cabildo de La Palma oficializó en sesión plenaria la denominación de Volcán de Tajogaite para esta erupción.

 

Extensión de la colada de lava con resaltado de edificios destruidos, el 23 de noviembre de 2021

 

19 de septiembre

Después de más de 25.000 pequeños terremotos que azotaron la isla durante ocho días, a las 15:10 (hora local)​ se inició la erupción en un paraje denominado Cabeza de Vaca, en el lugar de Las Manchas, municipio de El Paso.​ La erupción tenía inicialmente dos fisuras separadas por 200 metros, y ocho bocas.​ Autoridades como la Guardia Civil, que desplegó sobre el terreno a más de 120 efectivos, estimaron que el número total de evacuados podría superar los 10 000, consonante al recorrido que hiciese la lava hacia la costa. Igualmente y en prevención de que la lava cortase las carreteras de acceso a los núcleos costeros, se evacuó Puerto Naos, La Bombilla, El Remo y Charco Verde, que hubieran quedado incomunicados. También se cerraron al tráfico varias carreteras por prevención.

   

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A cidade de Pompeia foi destruida pelo Vesúvio há 1946 anos...

 

Pompeia foi outrora uma antiga cidade do Império Romano situada a 22 quilómetros da cidade de Nápoles, na Itália, no território do atual município de Pompeia. A antiga cidade foi destruída durante uma grande erupção do vulcão Vesúvio em 24 de agosto do ano 79 d.C.

     

    

A antiga cidade foi destruída durante uma grande erupção do vulcão Vesúvio no ano 79, que provocou uma intensa chuva de cinzas que sepultou completamente a cidade. Ela manteve-se oculta durante cerca de dezasseis séculos, até ser reencontrada, por acaso, em 1748. Cinzas e lama protegeram as construções e objetos dos efeitos do tempo, moldando também os corpos das vítimas, o que fez com que fossem encontradas do modo exato como foram atingidas pela erupção. Desde então, as escavações proporcionaram um sítio arqueológico extraordinário, que possibilita uma visão detalhada na vida de uma cidade dos tempos da Roma Antiga.

Classificada como Património Mundial pela UNESCO, juntamente com Herculano e Torre Annunziata, Pompeia é uma das atrações turísticas mais populares da Itália, com cerca de dois milhões e meio de visitantes por ano.

    

   

A erupção do Vesúvio em 79 foi uma das mais conhecidas e catastróficas erupções vulcânicas de todos os tempos. Nas cercanias as cidades romanas de Pompeia, Herculano, Estábia e Oplontis foram afetadas, com Pompeia e Herculano, sendo completamente destruídas. O Vesúvio espalhou uma nuvem mortal de rochas, cinzas e gases que chegou a uma altura de mais de 30 quilómetros, cuspindo lava e pedra-pomes a uma proporção de 1.5 milhão de toneladas por segundo e libertando no total uma energia térmica centenas de milhares de vezes maior do que a do bombardeamento de Hiroshima.

Estima-se que 16.000 cidadãos de Pompeia e Herculano morreram devido ao fluxo piroclástico hidrotermal de temperaturas superiores a 700 °C. Desde 1860, quando escavações sistemáticas passaram a ser realizadas em Pompeia, os arqueólogos descobriram nos limites da cidade as cascas petrificadas dos corpos decompostos de 1.044 vítimas.

 

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Já terminou a nona erupção do vulcão Grindavik, na Islândia...

 

The eruption observed from the Icelandic Coast Guard’s helicopter on 16 July 2025

 

On 16 July 2025 at 3:54 UTC, nearly three hours after a swarm of 4–6 km deep earthquakes exposed a south-north dike beneath the crater row, the ninth eruption broke out just south-east of Litla‑Skógfell.  The initial fissure, measuring 700–1,000 m, lengthened to roughly 2.4 km within eight hours. A parallel 500 m crack and advancing pāhoehoe flows expanded the lava field to over 3.2 km², as confirmed by ICEYE satellite imagery. Within 24 hours, the fissure fragmented into 10–12 active cones. By 19 July it had consolidated into about two or three cones and to a single cone by 22 July. As of 23 July, the lava field had expanded to 3.3 km² in area and 26.8 million m³ in volume. As in the February 2024 and May–June 2024 eruptions, this eruption interacted with groundwater, violently ejecting grey ash and smoke into the air in certain areas. Because earlier models had predicted the next eruption in autumn 2025, this mid‑July event caught volcanologists by surprise.

An evacuation was carried out in the area, affecting approximately 200 people at the Blue Lagoon and over 100 residents and visitors in the town of Grindavík, including around 20 to 30 campers at a local campsite. Two United Airlines aircraft headed for Keflavík Airport returned to their points of departure on the airline’s own initiative, without having received any specific advisories or instructions from Icelandic air traffic control. Access to the volcano is currently permitted, and conditions for visiting the eruption are considered the most favorable since the Fagradalsfjall eruptive series of 2021–2023. The location of the eruption, combined with the availability of parking facilities along the peninsula’s south coast, attracted large numbers of tourists and other visitors, resulting in full parking lots in the area. Some people were even seen walking on the recently cooled lava, most of them foreign tourists. This behaviour was also frequently observed during the previous eruptive series, and the Icelandic Meteorological Office warns that it is "life‑threatening", as the thin surface crust can collapse without warning, exposing molten lava beneath. The eruption did not cause any damage to infrastructure in the surrounding area.

Warnings were issued shortly after the onset of the eruption due to volcanic gas, and the highest sulfur dioxide (SO₂) levels were recorded in Njarðvík just a few hours after the eruption began, peaking at 6,284 µg/m³ (2,398.21 ppbv). During the first days, the eruption released a sulfur dioxide-rich plume over Reykjanesbær and into the Capital Region, where sulfur dioxide levels also reached a local record high since volcanic activity began on the Reykjanes Peninsula - exceeding 2,000 µg/m³ (763.28 ppb), compared to typical readings below 5 µg/m³ (1.91 ppb). About a week into the eruption, sulfur dioxide emissions from the fissure vent were around 100 kg/s but dropped significantly the following day to 25–44 kg/s. Within two weeks, volcanic gas emissions from the eruption led to a mild but visible haze of sulfate particles (SO₄) across the country, formed as sulfur dioxide reacted with moisture and oxygen in the atmosphere. This led to an increase and temporary burden on clinics and local health centres, as people experiencing various symptoms sought medical advice. Despite the situation, specialists emphasize that the pollution is not a "poison gas". In early August, volcanic tremor and explosive activity declined, coming to a complete halt on 4 August. On 5 August, the eruption was declared over, as police-operated drone imagery confirmed the absence of activity within the craters. 

 

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A erupção pliniana do Pinatubo, que afetou significativamente o clima da Terra, começou há 34 anos

The eruption column of Mount Pinatubo on June 12, 1991, three days before the climactic eruption

      

Mount Pinatubo is an active stratovolcano located on the island of Luzon, near the tripoint of the Philippine provinces of Zambales, Tarlac, and Pampanga. It is located in the Cabusilan Mountains separating the west coast of Luzon from the central plains. Before the volcanic activities of 1991, its eruptive history was unknown to most people. It was heavily eroded, inconspicuous and obscured from view. It was covered with dense forest which supported a population of several thousand indigenous people, the Aetas, who fled to the mountains during the Spanish conquest of the Philippines.

The volcano's Plinian/Ultra-Plinian eruption on June 15, 1991, produced the second largest terrestrial eruption of the 20th century after the 1912 eruption of Novarupta in the Alaska Peninsula. Complicating the eruption was the arrival of Typhoon Yunya bringing a lethal mix of ash and rain. Successful predictions at the onset of the climactic eruption led to the evacuation of tens of thousands of people from the surrounding areas, saving many lives, but the surrounding areas were severely damaged by pyroclastic flows, ash deposits, and subsequently, by the lahars caused by rainwaters re-mobilizing earlier volcanic deposits causing extensive destruction to infrastructure and altering the river systems months to years after the eruption.

The effects of the eruption were felt worldwide. It ejected roughly 10,000,000,000 tonnes  or 10 km³ of magma, and 20,000,000 tonnes of SO2, bringing vast quantities of minerals and metals to the surface environment. It injected large amounts of particulate into the stratosphere – more than any eruption since that of Krakatoa in 1883. Over the following months, the aerosols formed a global layer of sulfuric acid haze. Global temperatures dropped by about 0.5 °C and ozone depletion temporarily increased substantially.
    

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Maurice e Katia, não vos esqueceremos...

Katia e Maurice Kraft, um casal de vulcanólogos, morreram na erupção do vulcão Unzen há 34 anos...

   

Katia Krafft (Mulhouse, 17 April 1942 – Unzen, 3 June 1991) and her husband, Maurice Krafft (Guebwiller, 25 March 1946 – Unzen, 3 June 1991) were French volcanologists who died in a pyroclastic flow on Mount Unzen, in Japan, on June 3, 1991. Their obituary appeared in the Bulletin of Volcanology, (vol. 54, pp 613–614).

Maurice and Katia were known for being pioneers in filming, photographing and recording volcanoes, often getting within feet of lava flows. They met at Strasbourg University, and their career as volcano observers began soon after. With little money, they saved up for a trip to Stromboli and photographed the eruption. Finding that people were interested in this documentation of eruptions, they soon made a career out of this, which afforded them the ability to travel the globe.

The Kraffts were often the first to arrive at an active volcano, and were respected and envied by many volcanologists. Their footage of the effects of volcanic eruptions was a considerable factor in gaining the cooperation of local authorities faced with volcanic threats. One notable example of this was after the onset of activity at Mount Pinatubo in 1991, where their video of the effects of the eruption of Nevado del Ruiz in Colombia was shown to large numbers of people, including Philippine President Cory Aquino, and convinced many skeptics that evacuation of the area would be necessary.

In June 1991, while filming eruptions at Mount Unzen, they were caught in a pyroclastic flow which unexpectedly swept out of a channel others had been flowing down and onto the ridge they were standing on. They were killed instantly, along with 40 journalists also covering the eruptions.

The work of the Kraffts was highlighted in a video issue of National Geographic, which contained a large amount of their film footage and photographs as well as interviews with both. Maurice is famous for saying in the video that "I am never afraid because I have seen so much eruptions in 23 years that even if I die tomorrow, I don't care," coincidentally on the day before his death. Volcano: Nature's Inferno. [videorecording]. Washington, DC: National Geographic Society. 2003.

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David A. Johnston morreu há quarenta e cinco anos... (Vancouver! Vancouver! This is it!)

The last picture ever taken of Johnston, 13 hours before his death at the eruption site

 

David Alexander Johnston (Chicago, December 18, 1949 – Mount St. Helens, May 18, 1980) was an American United States Geological Survey (USGS) volcanologist who was killed by the 1980 eruption of Mount St. Helens in the U.S. state of Washington. A principal scientist on the USGS monitoring team, Johnston was killed in the eruption while manning an observation post six miles (10 km) away on the morning of May 18, 1980. He was the first to report the eruption, transmitting "Vancouver! Vancouver! This is it!" before he was swept away by a lateral blast; despite a thorough search, Johnston's body was never found, but state highway workers discovered remnants of his USGS trailer in 1993.

Johnston's career took him across the United States, where he studied the Augustine Volcano in Alaska, the San Juan volcanic field in Colorado, and long-extinct volcanoes in Michigan. Johnston was a meticulous and talented scientist, known for his analyses of volcanic gases and their relationship to eruptions. This, along with his enthusiasm and positive attitude, made him liked and respected by many co-workers. After his death, other scientists lauded his character, both verbally and in dedications and letters. Johnston felt scientists must do what is necessary, including taking risks, to help protect the public from natural disasters. His work, and that of fellow USGS scientists, convinced authorities to close Mount St. Helens to the public before the 1980 eruption. They maintained the closure despite heavy pressure to re-open the area; their work saved thousands of lives. His story became intertwined with the popular image of volcanic eruptions and their threat to society, and a part of volcanology's history. To date, Johnston, along with his mentee Harry Glicken, is one of two American volcanologists known to have died in a volcanic eruption.

Following his death, Johnston was commemorated in several ways, including a memorial fund established in his name at the University of Washington to fund graduate-level research. Two volcano observatories were established and named after him: one in Vancouver, Washington, and another on the ridge where he died. Johnston's life and death are featured in several documentaries, films, docudramas and books. A biography of his life, A Hero on Mount St. Helens: The Life and Legacy of David A. Johnston, was published 2019.

 

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