Suchergebnisse

AbstractOver large regions exposed to natural disasters, cascading effects resulting from complex or concatenated natural processes may represent a large portion of total risk. Populated high‐mountain environments are a major concern, and methods for large‐scale quantitative risk analyses are urgently required to improve risk mitigation. This article presents a comprehensive quantitative rockfall risk assessment over a large archetypal valley of the Andean mountains, in Central Chile, which integrates a wide spectrum of elements at risk. Risk is expressed as an expected damage both in monetary terms and casualties, at different scales relevant for decision making. Notably, total rockfall risk is divided into its main drivers, which allows quantifying seismically induced rockfall risk. For this purpose, the local seismic hazard is quantified and the yield acceleration, that is, acceleration required to initiate rockfall, is determined at the regional scale. The probability of failure is thereafter derived in terms of annual frequency of rockfall initiation and integrated in the quantitative risk assessment (QRA) process. Our results show the significant role of seismic activity as the triggering mechanism of rockfalls, and highlight elements at risk that have a major contribution to the total risk. Eventually a sensitivity analysis is conducted to (i) assess the robustness of obtained risk estimates to the data and modeling choices and (ii) identify the most influential assumptions. Our approach evidences the feasibility of large‐scale QRAs in sensitive environments and opens perspectives for refining QRAs in similar territories significantly affected by cascading effects and multihazards.

The mid-17th century is characterized by a cluster of explosive volcanic eruptions in the 1630s and 1640s, climatic conditions culminating in the Maunder Minimum as well as political instability and famine in regions of Western and Northern Europe as well as China and Japan. This contribution investigates the sources of the eruptions of the 1630s and 1640s and their possible impact on contemporary climate using ice-core, tree-ring and historical evidence, but will also look into the socio-political context in which they occurred and the human responses they may have triggered. Three distinct sulfur peaks are found in the Greenland ice core record in 1637, 1641-42 and 1646. In Antarctica, only one unambiguous sulfate spike is recorded, peaking in 1642. The resulting bipolar sulfur peak in 1641-1642 can likely be ascribed to the eruption of Mount Parker (6°N, Philippines) on December 26, 1640, but sulfate emitted from Koma-ga-take (42°N, Japan) volcano on July 31, 1641, has potentially also contributed to the sulphate concentrations observed in Greenland at this time. The smaller peaks in 1637 and 1646 can be potentially attributed to the eruptions of Hekla (63°N, Iceland) and Shiveluch (56°N, Russia), respectively. To date, however, none of the candidate volcanoes for the mid-17th century sulphate peaks have been confirmed with tephra preserved in ice cores. Tree-ring and written sources point to cold conditions in the late 1630s and early 1640s in various parts of Europe, and to poor harvests. Yet the early 17th century was also characterized by widespread warfare across Europe – and in particular the Thirty Years' War (1618–1648) – rendering any attribution of socio-economic crisis to volcanism challenging. In China and Japan, historical sources point to extreme droughts and famines starting in 1638 (China) and 1640 (Japan), thereby preceding the eruptions of Koma-ga-take (July 31, 1640) and Mount Parker (January 4, 1641). The case of the eruption cluster between 1637 and 1646 and the climatic and societal ...

The mid-17 th century is characterized by a cluster of explosive volcanic eruptions in the 1630s and 1640s, deteriorating climatic conditions culminating in the Maunder Minimum as well as political instability and famine in regions of Western and Northern Europe as well as China and Japan. This contribution investigates the sources of the eruptions of the 1630s and 1640s and their possible impact on contemporary climate using ice-core, tree-ring and historical evidence, but will also look into the socio-political context in which they occurred and the human responses they may have triggered. Three distinct sulfur peaks are found in the Greenland ice core record in 1637, 1641–42 and 1646. In Antarctica, only one unambiguous sulfate spike is recorded, peaking in 1642. The resulting bipolar sulfur peak in 1641–1642 can likely be ascribed to the eruption of Mount Parker (6° N, Philippines) on December 26, 1640, but sulfate emitted from Koma-ga-take (42° N, Japan) volcano on July 31, 1641, has potentially also contributed to the sulphate concentrations observed in Greenland at this time. The smaller peaks in 1637 and 1646 can be potentially attributed to the eruptions of Hekla (63° N, Iceland) and Shiveluch (56° N, Russia), respectively. To date, however, none of the candidate volcanoes for the mid-17 th century sulphate peaks have been confirmed with tephra preserved in ice cores. Tree-ring and written sources point to severe and cold conditions in the late 1630s and early 1640s in various parts of Europe, and to poor harvests. Yet the early 17 th century was also characterized by widespread warfare across Europe – and in particular the Thirty Years' War (1618–1648), rendering any attribution of socio-economic crisis to volcanism challenging. In China and Japan, historical sources point to extreme droughts and famines starting in the late 1630s, and thus preceding the eruptions by some years. The case of the eruption cluster in the late 1630s and early 1640s and the climatic and societal conditions recorded in its aftermath thus offer a textbook example of difficulties in (i) unambiguously distinguishing volcanically induced cooling, wetting or drying from natural climate variability, and (ii) attributing political instability, harvest failure and famines solely to volcanic climatic impacts. This example shows that the impacts of past volcanism must always be studied within the contemporary socio-economic contexts, but that it is also time to most past reductive framings and sometimes reactionary oppositional stances in which climate (and environment more broadly) either is or is not deemed an important contributor to major historical events.