Disaster Management for Volcanoes

Volcanoes are a difficult natural hazard to manage in some ways, and very straightforward in other ways. For long periods of time they are dormant and seem like any ordinary mountain, but during their fantastic and terrifying eruptions, volcanoes remind us that every day is a good day for disaster management, not just the day of a catastrophe.

History

• Volcanoes, though infrequent in their eruptions, pose serious risks to human society. Perhaps the most famous evidence for why people should take disaster management of volcanoes seriously can still be seen at the ruins of Pompeii in Italy, under the shadow of Mt. Vesuvius. Roman citizens of Pompeii were caught unaware by an eruption of Vesuvius, burying the town in debris and freezing many in a tomb of volcanic ash. So sudden was the event, and so rapidly were people trapped, that eerie castes made of ash can be found in fleeing and hiding poses. In more modern times, many remember the 1980 eruption of Mt. St. Helens in Washington State, which devastated the surrounding area for miles and covered many towns in wind-blown ash that fell like snow.

Lava

• Usually lava flows aren't the biggest threat from volcanoes, despite the visually impressive nature of lava. It is fortunate that lava isn't the primary threat of volcanoes, because there are few options in mitigating against it. In areas like Hawaii and Iceland, were the lava is less viscous and flows far, residents have plenty of warning to pack of bare necessities and evacuate their house, if they are in the path of lavaflows. Way in which lava flows can be managed well is to utilize the newly formed land masses post-disaster. In Iceland, volcanic eruptions in the mid 90s poured massive amounts of lava and created new landmass, which is now inhabited.

Pyroclastic Flow and Ash

• The farthest reaching danger of volcanoes which must be managed is the pyroclastic flow and the ashclouds. Pyroclastic flows are vast masses of hot gas, rock and ash which blows down a mountain at incredible speed, burying and burning everything it is path. Like many aspects of volcanic eruptions, there is little that can be done to directly stop this, but having evacuation plans and warning systems in place can prevent casualties.

  Ash clouds are not as life threatening, but farther reaching. For personal safety, air filters and painter's masks are a cheap and important defense against lung irritation from breathing ash. High sloped roves also prevent building collapse under the weight of fallen ash, which can be treated much like areas which receive high snowfall.

Lahars

• Typically, there aren't many people in direct path of the pyroclastic flow or lava range of a volcanic eruption. Much more threatening is the flow path of lahars, which are muddy torrents of melted snow and debris that occur during or even prior to a volcanic eruption. These slurries can have the consistency of wet cement, and possess massive kinetic energy as they flow down mountains into river channels and low lying regions. Cities in danger of lahar paths should practice lahar drills like they would fire drills. There is virtually no stopping a lahar, so the best management practice is to build out of the expected path, and to have evacuation routes to elevated areas.

Seismic Warning Systems

• Most of the time, volcanoes don't go off completely unexpected. Small earthquakes and gaseous emissions usually precede an eruption. Modern seismic sensors are the best tool geologists have for predicting an eruption and recommending evacuations of nearby people.