Volcano

Since the 1991 climatic eruption of Pinatubo, various hazards have affected the surrounding areas. The most significant of these involve the re-deposition of pyroclastic flow and fall deposits as lahars, deposit-derived pyroclastic flows, and phreatic explosion ash fall. Many of these processes occurred in areas that are inaccessible for ground observation and monitoring. A case in point is the potential hazard that currently threatens the low-lying areas along the Maraunot-Bucao river system should a significant lake breakout occur from the 1991 crater. Sequential remote sensing (RS) data sets, which include multi-temporal ERS, SIR-C, SPOT, TOPSAR/AIRSAR, Landsat 7 and Ikonos scenes, provide an unparalleled perspective to reconstruct the sequential development of the Pinatubo landscape and map the areas of the ignimbrite sheets that are being eroded as well as the encroachment of lahar fans. Multiple acquisition using different imaging techniques over the same area yields different...

Fumarolic activity supports the growth of mat-like photoautotrophic communities near the summit (at 6,051 m) of Socompa Volcano in the arid core of the Andes mountains. These communities are isolated within a barren, high-elevation landscape where sparse vascular plants extend to only 4,600 m. Here, we combine biogeochemical and molecular-phylogenetic approaches to characterize the bacterial and eucaryotic assemblages associated with fumarolic and nonfumarolic grounds on Socompa. Small-subunit rRNA genes were PCR amplified, cloned, and sequenced from two fumarolic soil samples and two reference soil samples, including the volcanic debris that covers most of the mountain. The nonfumarolic, dry, volcanic soil was similar in nutrient status to the most extreme Antarctic Dry Valley or Atacama Desert soils, hosted relatively limited microbial communities dominated by Actinobacteria and Fungi , and contained no photoautotrophs. In contrast, modest fumarolic inputs were associated with ele...

The passage of the Earth through dense clumps of dark matter, the presence of which is predicted by certain cosmologies, would produce large quantities of heat in the interior of this planet through the capture and subsequent annihilation of dark matter particles. This heat would lead to ...

ABSTRACT The main problem posed by the 2002-2003 eruptive crisis at Stromboli was in assessing the flank stability of the volcanic edifice. Indeed, this eruptive crisis has been characterized by important effusive and collapse events inside the Sciara del Fuoco sector collapse area: in particular, two flank sector collapses in the aerial and submarine part of the edifice and the opening of a fracture set close to gliding plane in the summit part of the Sciara del Fuoco sector collapse. Detailed fluid flow mapping and reiterative profiles carried out with self-potential, temperature, and soil gas measurements since 1994 in the Fossetta-Sciara del Fuoco-Fossa area, show the importance of old structural boundaries, such as the Large Fossa crater, in the opening of part of the 2002-2003 set of fractures. Within this structural framework, other morphological changes occurred during the eruptive crisis, such as the opening of new sets of fracture and collapse events. These were probably located along other crater boundaries formed since the largest paroxysmal event of September 1930, which dramatically modified the morphology inside the Large Fossa crater area. The multidisciplinary approach to fluid flow measurements during an eruptive crisis demonstrates the powerful potential of these techniques as a complement to deformation measurements in assessing the weakness planes of a volcanic edifice and the risk of sector collapses.

Large tropical volcanic eruptions can have considerable impact on climates and societies far away from the physical source of the eruption. Past examples of how volcanism caused abrupt climatic changes, and how societies responded to such changes, may provide us with potential lessons to help us better prepare for the changes that climate change will bring. This paper explores the climatic, agricultural and societal responses to tropical eruptions in the Finnish province of Southern Ostrobothnia during the seventeenth century. Our results suggest that in the studied area more than half of the seventeenth-century agricultural crises which had traceable human consequences resulted from volcanism caused cooling. A sharp agricultural response followed every large tropical eruption. Moreover, sudden impoverishment, and in some cases even elevated mortality and famine, succeeded these agricultural crises. Thus, there is strong evidence that climatic changes caused by volcanism can directly paralyze sensitive food systems that are based on primary production. In this regard, if geoengineering solutions, like emulating volcanic forcing to cool global climate, are considered to be a future mitigation strategy, the case study presented here stresses the need to explore all possible unintended human consequences of any such solutions.