Well, they're right in one respect: stay in the path of a lava flow and you will likely cease being alive. You can probably out-walk most lava flows. So, what is it that makes volcanoes so deadly if it isn't the copious volumes of lava they can produce? Here's a little countdown of what I think are the most dangerous volcanic hazards based on the number of deaths associated with them, the potential for damage to houses and infrastructure, the frequency with which they occur and the difficulty of avoiding them.
Lava Flows: After all that pre-amble about lava flows , here they are! Though lava flows may not cause many fatalities, the potential damage to infrastructure and homes is very high. Lava flows are also very common at certain types of volcanoes, so with that combination of frequency and destructiveness, we need to take lava flows seriously.
However, the lava can be deadly in rare cases. This can happen when the composition and temperature of the lava means it is especially runny, so it travels fast.
An eruption of Nyiragongo in the Democratic Republic of the Congo produced lava flows that moved through the city of Goma killing dozens. Tsunamis: Tsunamis can be generated by geologic events other than eruptions -- in fact, they are more common with earthquakes. However, volcanoes can produce these deadly ocean waves when part of the volcano collapses during an eruption.
Most recently, the eruption of Anak Krakatau killed over people when most of the relatively-small cinder cone collapsed during an eruption. The predecessor to Anak Krakatau -- Krakatau itself -- generated a massive m tsunami when it collapsed into a caldera in That eruption and tsunami killed over 35, people along the Sunda Strait in Indonesia. The lahar also entered Spirit Lake, which can be seen in the lower left corner. About years ago, the collapse of weakened rocks caused a large lahar at Mount Rainier.
Called the Electron Mudflow, the lahar traveled through the Puyallup River valley. Today, those numbers are greater, and the next lahar in the Puyallup Valley could create significant impacts on the community and economy. To learn more about general lahar hazards and their effects, visit the Volcano Hazards Program lahars webpage.
In this video Scientist Richard Iverson describes how lahars form and shows experiments that help scientists to model lahar behavior. To understand lahars, scientists observe and quantify what happens when these events occur naturally, derive equations to describe lahar behavior, and perform controlled experiments in a feet m long debris flow flume. The results help us to understand flow dynamics and develop improved technologies for mitigating the destructive effects of debris flows.
Because of the danger presented by lahars, scientists are ready to deploy lahar-detection systems when eruptions are imminent. The lahar proceeded in three major pulses. One of the lahars virtually erased Armero; three-quarters of its 28, inhabitants were killed. Traveling at about 6 meters 20 ft per second, the second lahar lasted for thirty minutes and was followed by smaller pulses. A third major pulse brought the lahar's overall duration to roughly two hours. By that point, 85 percent of Armero was enveloped in mud.
Pierce County has mapped and installed signs for volcano evacuation routes in case of lahar. In evacuation plans, the initiative that has guided all interventions so far is the program of the International Decade for the Reduction of Natural Disasters, , declared by United Nations after the Nevado Ruiz disaster.
A basic part of the program is to foster a culture for the mitigation of natural disasters, since an emergency plan is of little use if it is not known and assumed by those at risk. As for the reduction of the exposure, for many governments the problem is the source of wealth generated by a volcano around it: its sediments favor a fertile agriculture, they are a tourist attraction, they provide geothermal energy, thermal waters and construction materials.
For this reason, many volcanoes, especially those located in disadvantaged areas, are triggers of population growth around them, increasing the exposure of people and goods, and therefore the risk of a catastrophe. The development of methodologies for the objective estimation of risk, scientific dissemination on a large scale and the implementation of educational programs for the knowledge of the territory and its physical features are key factors to reduce vulnerability and increase post-disaster resilience.
The lost sea Water, the right to a decent life Water for thought. To foster a sensibility and awareness of the water problematic around the world. Two options of donations. Stay Informed. Find out what we do, spread the word and start collaborating. Lahars: the threat of water under the volcano. The challenges of risk reduction Reducing the risk caused by volcanic eruptions is one of the major challenges for civil protection in countries with the largest exposed populations.
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