Capturing a new episode of unrest at Santorini volcano, Greece

圣托里尼是爱琴海（希腊）的一座主要火山，以大约3,600年前发生的一次大喷发（米诺斯火山喷发）而闻名，并对整个东地中海造成了重大的环境和政治影响。那次喷发形成了一个巨大的破火山口，现在被海水淹没，圣托里尼的火山活动被限制在破火山口中间的一个小区域。在过去的500年里，发生了六次中度喷发，形成了年轻的Nea和Palea Kameni岛。这些喷发通常发生在没有什么警告的情况下-一些非常小的地震;岛屿的一些运动（上下），以及该地区许多温泉周围海水的一些变化。每一次喷发都伴随着熔岩的缓慢挤出，伴随着几次更剧烈的爆炸和熔岩块、火山灰和有毒气体的喷出。最后一次也是最小的一次喷发发生在1950年。自1950年以来，圣托里尼岛一直很平静-很少有地震，也很少有气体排放。最近，在野外工作中，我们测量到最年轻的火山口附近的气体排放率大幅增加。我们现在还看到圣托里尼主岛（用全球定位系统测量）和新卡梅尼主岛（用卫星测量）的一些快速移动：这表明这些岛屿每月上升几厘米。还有一系列非常小的地震，其中一些大到足以让岛上的居民感到。我们认为，所有这些证据表明，圣托里尼已经开始了一个重要的“动荡”阶段。我们所看到的动荡模式与历史上一些火山爆发前所报告的信号相似，我们建议进行一次密集的实地活动，以测量与这座主要火山口火山膨胀相关的地面变形和气体排放。由于科学家在动荡时期很少有机会监测火山口火山的行为，我们真的还不知道如何区分背景活动和喷发前可能发生的活动，至少直到喷发发生前的很短时间。出于这个原因，我们希望利用这个难得的机会，在一个安静但危险的火山上测量浅层扰动的变化。

Santorini is a major volcano in the Aegean sea (Greece), which is best known for a major eruption (the Minoan eruption) that occurred about 3,600 years ago, and has been implicated in major environmental and political impacts across the eastern Mediterranean. Since that eruption, which formed a large caldera, now flooded by the sea, volcanic activity at Santorini has been restricted to a small region in the middle of the caldera. Over the past 500 years, six moderate eruptions have taken place, forming the young islands of Nea and Palea Kameni. These eruptions have usually happened with little warning - a few very small earthquakes; some movements of the islands (up and down), and some changes in the seawater around the many hotsprings in the area. Each of these eruptions has involved the slow squeezing out of lava, with a few more dramatic explosions and the ejection of blocks of lava, ash and noxious gases. The last, and smallest, of these eruptions took place in 1950. Since 1950, Santorini has been quiescent - with very few earthqaukes, and very little gas emission. Recently, during fieldwork, we measured a large increase in gas emission rates from near the youngest volcanic vent. We have also now seen some rapid movements of the main island of Santorini (measured by GPS), and of New Kameni (measure by satellite): these show that the islands are being lifted up by a few centimetres per month. There has also been a major swarm of very small earthquakes, some of which have been large enough to be felt by the residents of the islands. We think that all of this evidence shows that Santorini has begun a significant phase of 'unrest'. The pattern of unrest that we have seen is similar to the signals reported that happen before some of the historical eruptions, amd we propose an intensive field campaign to measure the ground deformation and gas emissions, associated with the inflation of this major caldera volcano. Because there have been very few opportunities for scientists to monitor the behaviour of caldera volcanoes during periods of unrest, we really don't yet know how to distinguish between background activity, and activity which might happen before an eruption, at least until just a very short time before an eruption happens. For this reason, we wish to use this rare opportunity to measure the changes with a shallow disturbance at a quiescent but dangerous volcano.