Predicting the effects of climate change on alpine rock slopes: Evaluation of paraglacial and periglacial drivers of rockfall in the European Alps

预测气候变化对高山岩石斜坡的影响：评估欧洲阿尔卑斯山落石的冰旁和冰缘驱动因素

基本信息

批准号：
316624774
负责人：
Dr. Daniel Dräbing
金额：
--
依托单位：
Departement Fysische Geografie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/316624774?language=en
关键词：
Predicting effects climate change alpine

项目摘要

Rockfall from alpine rockwalls represents a hazard to human life and infrastructure but also a natural process of rock slope evolution. Two contrasting hypotheses currently exist which aim to explain rock slope evolution: (1) a paraglacial adjustment of the rockwalls with increasing frequency due to deglaciation and a subsequent asymptotically decline of adaption and (2) a frost-weathering dominant adaption with steady-state rates. Climate change will affect alpine systems by an increase of temperatures and a decrease of frost weathering activity and glaciated area. Hypothesis (1) suggests an increase of rockfall frequency due to deglaciation. On contrary, hypothesis (2) expects a decrease of rockfall frequency due to the dislocation of highest frost cracking activity to higher altitudes. Both hypotheses are based on assumptions which have been never tested or validated in the field. As a consequence, the future adaption of rockwall to climate change is unknown.Very few studies focus on rockfall after deglaciation on different time scales. On the Holocene time scale, rockfall is relied to increase post glaciation. The findings are based on dating and derivation of erosion rates without incorporating mechanical or thermal rockwall properties. As a result, the observed increase cannot be traced back to paraglacial adjustment or frost weathering processes. On the contrary, rock slope erosion in recently deglaciating areas can integrate mechanical and thermal rockwall properties. However, the period to establish frequency-distributions is too short to draw conclusions on potential evolution due to climate change.This approach integrates Holocene and recent rock slope erosion in one investigation. The objectives of the study are (1) to quantify the thermal regime of the rockwalls, (2) to quantify the response of mechanical regime and establish a short-term erosion rate. Furthermore, the study will (3) increase the process understanding of frost weathering and (4) quantify long-term rock slope erosion. In a space-for-time substitution approach (5) a rock slope erosion model will be developed to bridge short-term and long-term rock slope failure. Fieldwork will take place in the Hungerli Valley, Valais Alps, and in the Gaisberg Valley, Ötztal Alps. State-of-the-art geomorphological, geotechnical and geophysical methods including refraction seismic tomography, electric resistivity tomography, terrestrial laserscanning, laboratory frost-weathering simulation and Be-10 dating will be combined to address the research objectives. Expected results include the temporal and spatial distribution of permafrost and frost weathering processes, the short-term adaption of rockwalls, an increase of understanding of frost weathering processes, a frost weathering model, a rock slope erosion model bridging short- and long-term rock slope erosion and the prediction of future rock slope evolution in the context of climate change and increased deglaciation.

阿尔卑斯式岩壁的岩石坠落代表着对人类生活和基础设施的危害，也代表了岩石斜率进化的自然过程。目前存在两个对比的假设，旨在解释岩石斜率的演变：（1）冰盘对岩壁进行冰盘调节，由于退化而增加频率和随后的适应性下降，以及（2）（2）（2）霜冻的主要适应性优势适应稳定状态。气候变化将通过温度的升高以及霜冻风化活动和冰川面积的降低来影响高山系统。假设（1）表明由于脱气引起的岩石频率增加。相反，假设（2）预计，由于最高霜冻裂纹活性脱位至较高的高度，落叶频率会降低。这两个假设均基于从未在现场测试或验证的假设。结果，岩壁对攀爬变化的未来适应是未知的。很少有研究重点是在不同时间尺度上进行脱落后的落叶。在全新世的时间尺度上，岩石降低了以增加冰川后。这些发现是基于侵蚀速率的日期和推导，而没有增加机械或热岩壁特性。结果，观察到的增加无法追溯到冰片冰调节或霜冻风化过程。相反，最近脱气区域中的岩石斜率侵蚀可以整合机械和热岩壁的性能。但是，建立频率分布的时期太短了，无法得出由于气候变化而导致的潜在演变的结论。这种方法将全新世和最近的岩石斜率侵蚀整合在一项投资中。研究的目标是（1）量化岩壁的热状态，（2）量化机械状态的响应并建立短期侵蚀率。此外，该研究将（3）在空间替代方法（5）中（5）将开发出岩石斜率侵蚀模型，以弥合短期和长期的岩石斜率故障。实地考察将在阿尔卑斯山瓦莱斯河谷和Ötztal阿尔卑斯山的盖斯伯格山谷举行。最先进的地貌，岩土技术和地球物理方法，包括折射地震层析成像，电抗性层析成像，陆地laserscanning，实验室霜冻 - 冻结模拟和BE-10级别，以解决研究目标。 Expected results include the temporary and spatial distribution of permafrost and frost weathering processes, the short-term adaptation of rockwalls, an increase of understanding of frost weathering processes, a frost weathering model, a rock slope erosion model bridging short- and long-term rock Slope erosion and the prediction of future rock slope evolution in the context of climate change and increased deglaciation.