The ongoing debate about the effects of changes in the high-mountain cryosphere on rockfalls and rock avalanches suggests a need for more knowledge about characteristics and distribution of recent rock-slope instabilities. This paper investigates 56 sites with slope failures between 1900 and 2007 in the central European Alps with respect to their geological and topographical settings and zones of possible permafrost degradation and glacial recession. Analyses of the temporal distribution show an increase in frequency within the last decades. A large proportion of the slope failures (60 %) originated from a relatively small area above 3000 m a.s.l. (i.e. 10 % of the entire investigation area). This increased proportion of detachment zones above 3000 m a.s.l. is postulated to be a result of a combination of factors, namely a larger proportion of high slope angles, high periglacial weathering due to recent glacier retreat (almost half of the slope failures having occurred in areas with recent deglaciation), and widespread permafrost occurrence. The lithological setting appears to influence volume rather than frequency of a slope failure. However, our analyses show that not only the changes in cryosphere, but also other factors which remain constant over long periods play an important role in slope failures.
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机译:有关高山冰冻圈变化对落石和雪崩的影响的持续辩论表明,需要更多有关近期岩质边坡不稳定性的特征和分布的知识。本文针对中欧阿尔卑斯山在1900年至2007年之间发生的56个坡度破坏的站点进行了地质和地形设置以及可能的多年冻土退化和冰川衰退的区域方面的调查。对时间分布的分析表明,最近几十年来频率的增加。很大一部分坡度破坏(60%)来自3000 m a.s.l.以上相对较小的区域。 (即整个调查区域的10%)。超过3000 m a.s.l.的分离区比例增加。推测这是多种因素综合作用的结果,即较大比例的高斜坡角,由于近期冰川退缩而导致的高冰川风化(几乎一半的斜坡破坏发生在最近的冰消地区)以及广泛的多年冻土发生。岩性设置似乎影响体积而不是斜坡破坏的频率。但是,我们的分析表明,不仅冰冻圈的变化,而且长期保持不变的其他因素在边坡破坏中也起着重要作用。
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