多年冻土是指>地面或媒介,(包括岩石、土壤和有机物质)与年平均气温小于0°C连续至少2年。光滑的外观了解冻土墙可以解释的工作。冻土的特征是一个活跃的层,这一层通常在表面每年冬季冻结和解冻在夏季——这一层亚马尔半岛可以1 - 2米深取决于当地的地面特征(积雪深度、反照率、斜率、空气温度、导热系数、径流等)。地面面积含冰。然后我们假设这个坑是由甲烷泡沫逃离/爆炸事件后可以立刻粗糙和墙壁。扣除,不应当有一个活跃的层发现墙上爆炸后,这是第一次这地面(墙)暴露在空气中。在夏天的时候,0°C以上整个由于对流空气进入。地面是含冰(多孔或无形的冰,但仍然含冰)和放射层开始在墙上。由于垂直方向附近的墙壁,饱和土壤(或活性层的形成)不能站,因为一旦它融化深度超过其平衡限制,它底部的火山口下降由于引力,提供了一个新的冰冻表面(和周期持续到均衡可以几年)。解冻的沉积物中含冰的土壤可以很快达到饱和,进一步增加了重量和加速下降的时候。 Rugged and unequal surface are typically the first elements to thaw and fall. I took this picture about an hundred km from the featured crater. ![enter image description here][1]. This display a very ice-rich section of the Yamal Peninsula littoral in the course of erosion. This coastal section has been eroding for decades at least. At the top the active layer is light brown, and look dry (1 m deep). Just under this top-layer, the ice is poly-genetic : ice wedge ice-rich soil and massive ice can be seen as well. The active layer cannot stand on the side for the reasons I exposed in the previous paragraph (gravity). Side-note, the jagged edges were not initiated by anything related to pingo. It takes decades up to many centuries for a pingo to develop until its natural collapse. When it happen, a depression can form at its center - which could lead to a lake, but these are not overnight processes. Also, contours of the pingo mound would not appear as jagged edges if this was a pingo - the remains would appear pretty old and vegetated, alike the surrounding countryside. [1]: http://i.stack.imgur.com/XZovW.jpg