Surprise surprise? Not really.
It was no surprise to me that the USGS’s first unofficial ‘prepper’ post was a list of resources for educators and kids. It helps to have the end user understanding advisories, so we might as well start young.
So, we begin our hazards preparation series with what I know from experience appeals to students: volcanoes.
Are Volcanoes a Risk in North America?
Though living over 2000 miles west of the site, I experienced the ash from the 1980 eruption of composite volcano Mount St. Helen; I even remember entrepreneurs selling ash trays made from the ash-cloud deposits.
Although 61 people died from that explosion, generally not many people die from volcanoes in North America; nothing close to Indonesia’s totals which top the list.
That could change, of course, if the supervolcano under Yellowstone erupts.
Says Canada’s CBC: “A super volcanic eruption from Yellowstone would be immense – producing energy equivalent to the detonation of 1,000 nuclear bombs it would emit one thousand cubic kilometers of ash, which is enough volume to fill the Grand Canyon twice.” So, stay tuned for that? Yeah right!
Positives and Negatives of Volcanoes
Agricultural populations have historically located close to volcanoes because of the fertile soils: The lava and ash deposited during an eruption breaks down to create valuable nutrients.
Add to that the sustainable geothermal heat potential close to volcanoes, and you can imagine the cost-benefits of development in places such as Iceland and near Oregon’s Newberry Volcano.
In addition, the dramatic scenery around volcanoes attracts tourists, bringing income to areas where volcanic activity is constant. The world’s three most active volcanoes, Kilauea volcano on Hawaii, Etna in Italy and Piton de la Fournaise on La Réunion Island, for instance, attract guided tours mixing mountaineering with the thrill of seeing one of the nature’s most unpredictable events.
– But that’s the problem: The unpredictability of volcanic eruptions. You don’t want to be caught running down a hill in front of a hot-debris avalanche in some volcano-prone area of the world. And that’s exactly what can happen when there is little or no monitoring, or when an eruption goes undetected by instruments or unobserved by Volcanologists.
Volcanic Threats to Life and Property
Most hazards during eruptions are caused by what comes out of a volcano. And naturally, the most impact comes from the most violent explosions (kids like these because they’re dramatic). These can include:
- Lava flows- slow moving and a low risk to human life although they can destroy infrastructure;
- Pyroclastic flows- fast moving hot debris avalanches (upwards of 500 km/h) and hot (up to 7000 °C) clouds of ash and gas, and highly dangerous;
- Lahars- mud flowing downhill like wet concrete
- Ash clouds- slow moving, their weight can collapse buildings, can be destructive to crops and water supplies, high plumes (e.g. 15 000 feet from the Cleveland Volcano in the Aleutians) can affect air traffic, and the clouds can reach high atmosphere to create cooling and disrupt climate; and
- Lava Bombs- molten rocks called pumice that are thrown out of volcanoes and can start fires.
Monitoring Volcanic Activity
When a volcano explodes there are several classification systems for rating the event.
One is the 8-grade Volcanic Explosivity Index (VEI). A VEI of 3, such as Popocatépetl for instance, signifies a severe series of discrete, canon-like explosions that are short-lived, lasting for only minutes to a few hours, often with high-velocity ejections of bombs and blocks.
The USGS goal, however, is to go beyond such classifications and change from a reactive to a proactive volcano-monitoring strategy, an early warning system.
Using surface and satellite-based telemetered instrument-arrays of various types, the goal in all monitoring is to accurately detect and correctly interpret in a timely fashion such phenomena as:
- Pressure and temperature conditions changing in the magma along its path;
- The resultant geophysical (surface deformation and earthquakes generated beneath the volcano) and geochemical phenomena (mostly H2O with some CO2 and minor amounts of Sulfur, Cl , and F gases).