Some of the world’s baddest volcanoes, like Chile’s Chaitén volcano that erupted in 2008, are actually even worse than scientists previously thought. A study of Chaitén’s eruption revealed that locals only had 30 hours to to flee from first time they felt rumbling, not the weeks or months that it typically takes a volcano to go from tremors to eruption. That’s because Chaitén is a rhyolitic volcano; these volcanoes are largely fueled by a silica-based, very flow-resistant magma and they tend to build pressure over time before erupting violently [National Geographic News]. Thousands were able to escape before Chaitén’s blast, but scientists are warning that others living in the shadow of a rhyolitic volcano may not be so lucky.
The magma of the Chaitén volcano traveled up to 3 feet per second, according to the study published in Nature. It shot from a depth of more than five kilometres [3 miles] to the surface in about four hours…. The violent and unexpected nature of the blasts, together with their rarity, means the Chaiténeruption is the first rhyolite event to have been scientifically assessed in this way [ABC News]. In the U.S. there are large rhyolitic volcanoes in Wyoming, California, and New Mexico as well as in the Japanese islands and New Zealand’s Taupo Volcanic Zone. Scientists are saying that even though rhyolitic eruptions are rare, the study should serve as a warning call to step up monitoring of potentially active volcanoes.
译文:
一个使科学家震惊的强烈火山爆发
世界上一些喷发最为迅猛的火山，例如像2008年喷发的智利的 Chaitén 火山 ，实际上比起科学家先前预料的更糟。一个 对 Chaitén’s 火山喷发研究显示当地民众从他们第一次感到隆隆的雷鸣声中逃离仅有30个小时，据其特点从颤动到喷发既不是几个星期也不是几个月。那是因为 Chaitén是一个流纹质火山; 这些火山大规模喷发燃烧是以硅石为基础燃料的，在火山喷发之前大流量岩浆及硅石久而久之活动形成巨大压力[国家地理杂志消息]。 数以千计的人在 Chaitén’s火山喷发前能够得以逃离 ，但科学家提醒到那些生活在流纹岩质火山阴影下的人也许就没有那么幸运 。
火山岩浆向上喷发速度为每秒钟3英尺， 根据发行于大自然研究结果显示 。它从大约5公里的一个深源 [3英里] 到地表需用时间约为四小时…. 其猛烈及难以预料的自然爆发，及它们的罕见程度, 意味着Chaitén火山爆发已经被这样合乎逻辑地评估为第一个流纹岩活动 [美国广播公司消息]。在美国有很多大型流纹岩火山 。分布于怀俄明州，加利福尼亚，及新墨西哥像日本的岛屿及新新西兰岛的 Taupo火山带一样 。科学家宣称尽管流纹岩喷发极为罕见 ，但研究结果作为一个警示应逐渐加强对潜在活火山的检测。