—碧海孕珍珠，烈火生凤凰—

迪生 2016

圣多里尼岛（Santorini）是整个爱琴海地区里，景色最为出名的地方。但是比较少为人知的是：它其实是一座威力强大的火山。在上一集当中，我和大家提过：克里特岛Minoan古文化衰亡最可能的肇因，是圣多里尼岛在公元前1600-1500年间多次猛烈的爆发。为什么在爱琴海当中会有这样一座威力强大的火山呢？

自远古以来，地球表面的诸多板块就不断地在互相漂移。在最近的几百万年间，欧亚大陆板块、和非洲大陆板块，是持续地互相接近。在这个大环境下，爱琴海周边的几个小板块，有一些复杂的相对运动，我把它们标示在下两张图中。如果以欧亚大陆板块为基准，爱琴海板块是向西南漂移，而非洲大陆板块则是向北方漂移。在爱琴海板块和非洲大陆板块交界的地方，非洲大陆板块被挤压到爱琴海板块之下，形成了“海伦海沟”。

当沉降板块的前端，被推挤到某个深度之后，由于周围温度的上升，而开始液化成岩浆，同时也释出一些气体。因此，压力和浮力都同时增加，所以这些新岩浆会往上寻找空隙喷出，而形成火山。所以在距离板块沉降海沟某些距离的地方，常常有和海沟大致平行的火山岛弧。从“海伦海沟”往北的第二个岛弧，就是一个火山岛弧。而圣多里尼岛，就位在这个火山岛弧的大致中点。

在过去的几十万年间，圣多里尼火山就处在“爆发崩塌→填充隆起→爆发崩塌→填充隆起”的循环当中。下图是最近一次爆发前、后，陆地轮廓的大略比较。部分的火山口，在爆发后崩塌。所以这一系列的爆发，不但带来了巨量的气体、岩浆、和火山灰，后续的火山口崩塌，也会引起大型的海啸，严重损害克里特岛的北海岸城镇、以及靠近陆地的船队。顺便提一下：火山口中心附近的两座小岛，并不是当时爆发后残留的，而是由在那次大爆发的一千多年以后的几次小喷发的岩浆流，冷却形成的。也就是上述“填充隆起”的显现。

此次爆发崩塌后所遗留的最大岛，就是现代人所称的“圣多里尼岛”。它的名字“Santorini”是“Saint Irene”的拉丁文“Santa Irini”的缩写（此地曾经是罗马帝国的一部分）。而此地的原始希腊文名称，则是“Thera”。

近几十年来，考古学家在圣多里尼岛最南端，一个叫做Akrotiri的地方，挖掘出一座被厚厚的火山灰覆盖了的Minoan文化古城。它的建筑架构、器物型制、以至于壁画的风格、色彩、和内容，都和在克里特岛上发掘的相当近似。这说明了在火山爆发的前夕，圣多里尼岛已经是Minoan文化圈的一个重镇了。

圣多里尼岛的西侧，是陡峭高耸的火山口内壁。而岛上的现代重要城镇，也大都建在西岸。居高临下的美丽海景，陡坡上的屋宇层叠，再加上当地社区对房屋外部颜色的传统偏好，造就了许许多多宛如世外桃源的美丽镜头。

A brief description in English:

Santorini – A Phoenix from a Fiery Birth, part 1

Santorini can be touted as the best known scenic island in the Aegean region. Nevertheless, much less publicized is its calamitous birth.

The tectonic movement between Eurasian Plate and African Plate has led to a complex motion pattern among several platelets around the Aegean region, as shown in my first illustration above. As a result, the Aegean Platelet is moving southwestwards with respects to Eurasian Plate, whereas the African Plate is moving northwards, sinking beneath the Aegean Platelet in the southeastern portion of the Mediterranean Sea. This subduction creates a volcanic arc, whose center portion lies Santorini Island.

Between 1600 BC and 1500 BC, a series of catastrophic eruptions of Santorini Volcano brought about huge amount of volcanic gas and ash. Furthermore, the subsequent collapse of portions of the caldera sent huge tsunamis to the northern coast of Crete Island in the south. Both calamities greatly weakened the then prosperous Minoan Civilization, leading to its decline and subsequent conquest by Mycenaean Greek from the Greece Peninsula.

The remains of this volcanic eruption and collapse are several new islands, with Santorini being the largest and having high cliffs along its western shore, which is actually part of the caldera rim of the volcano. Several modern towns are built on the top of these precipitous cliffs, including the capital town of Fira near the mid-point of the west coast, and the well-known tourist town of Oia near the northeastern tip. The panoramic view of Aegean Sea, the streets and houses straddling on the steep slope, and the community adherence to building’s external color code, have formed many photogenic sceneries.@＃

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责任编辑：李梅