川西北高原山地灾害垂直地带性

The Vertical Zonality of Mountain Hazards on the North-western Plateau in Sichuan

由于形成山地灾害的多种自然因素具有垂直地带性,尤其作为主要动力因素的水,超过一定高度后由液态成为固态,从而也造成了山地灾害的垂直地带性,从高到低可分为冰雪型、冻融型和流水(含地下水)型等三个山地灾害垂直带,高低两带之间主体界线在川西北高原地区为4900m和3500m。各带均有其特有的山地灾害,其中冰雪型山地灾害主要有冰崩、雪崩、冰面湖崩决等;冻融型山地灾害有冻融土流、冻融滑塌、冻融坍塌、融冻泥流、寒冻岩屑流和冰湖溃决等;流水型山地灾害有滑坡、崩塌、泥石流、山洪、泥石流坝和滑坡坝溃决等。认清这些灾害分布的垂直地带性,对于在相应地带进行资源开发和经济建设时,避免、减轻或妥善处治其危害具有重要的现实意义。

Because the vertical zonality of many natural factors which cause the vertical zonality of mountain hazards, especially water, as the main dynamic factor, when the height out weigh a certain elevation, will change from liquid state to solidity, which induce the vertical zonality of mountain hazards. From the higher levels to the lower levels, mountain hazards zones of ice and snow type, freezing-melting type and running water type （ including groundwater） could be divided. The maim body limits between two neighboring zone are 4 900 meter and 3 500 meter on the north-western Plateau in Sichuan. There are many especial mountain hazards in every vertical zonality of mountain hazards, among them glacier avalanche, snow avalanche, glacial lake burst in the mountain hazards zone of ice and snow type; freezing-melting landslide, freezing-melting collapse, freezing-melting earth flow, melting-freezing mud flow, moraine lake burst in the mountain hazards zone of freezing-melting type; landslide, collapse, debris flow, mountain torrents, landslide dam and debris flow dam burst in the mountain hazards zone of running water type. These mountain hazards would cause great effects on society and economy development in north-western Plateau in Sichuan. If we pay more attention to them and take careful and skillful handling, the hazards would be avoided or lightened.