I remember a valcano that blew in Japan in 1991. the pyrochastic cloud of poisenous gas and ash is what killed people and not the lava
Very close… “Pyroclastic” (apologies if that was a typo). In addition to potentially deadly gasses, it also tends to be superheated, 4 to 500 F wouldn’t be at all unusual.
That was the eruption of Unzen-Fugendake, close to Nagasaki. 43 people died, policemen, firefighters, volcanologists and journalists. Toxic fumes were/are also a big issue in Miyake-jima. This is an island in the Pacific that’s pretty much a volcano sticking out of the water. Historical records going back 500 years show that it blows up every 50 years or so. The volcano erupts, destroys the village, people leave, they come back, the volcano erupts, destroys the village, people leave, come back… The last time it erupted was in 2000. The whole island was completely off-limits until 2005 because the volcano is continuously shrouding it in deathly fumes. Over 40% of it is still not safe to get into.
The cool thing about Sakurajima and Kagoshima is that they actively use the mountain to sell the city to tourists. “Come visit us, we have a lovely fuming volcano in our harbour!”
From work, if the weather is good, I can see the glorious Ontake-san (that’s pretty much what it looks like to me). It’s not really close to any major city, but as someone who grew up in one of the least geologically active places on Earth, the thought of seeing an active volcano out my window is exciting.
I know the Italian government have been worried for some time about the Naples area. Vesuvius, they reckon, is supposed to blow big about once every 1500 years, and it has now been almost 2000 years since the last mega blow which destroyed Pompeii. Their biggest worry is evacuation - they estimate that there’s about 500,000 people living on the slopes of vesuvius who would struggle to get out, as the roads are already heavily clogged. This isn’t even including the impact on Naples itself from the fall-out.
I’m a Seattle resident who has participated in many disaster planning sessions and drills, and whose grandfather is a geologist.
It’s very unlikely that an eruption of Rainier would result in classic lava flows like you see on Hawaii or in National Geographic documentaries. Our geology isn’t the same. The free-flowing glowing-orange molten rock in the movie Dante’s Peak was greeted with hoots of derision in these parts.
A much more significant risk for volcanoes in our area is the flooding that results when several million cubic feet of glacier suddenly melts all at once. The mud mixes with sulfurous ash, creating a toxic stew that barrels downhill like a liquid freight train. Depending on prevailing winds, Northwest cities, including Seattle, could be buried in choking ash; certainly our transportation infrastructure would be fucked, with roads and bridges erased by the aforementioned flooding, making it difficult to coordinate evacuation and rescue/relief. Also our water supply would probably be contaminated. An eruption of Rainier, probably, would be (1) an immediate decent-sized catastrophe followed by (2) even more serious effects in the days following. The worst damage wouldn’t be caused by the initial Kaboom.
The up side is that we’ll most likely have at least a little warning before this happens. Mt. St. Helens yawned and stretched for many months before popping its cork; there’s no reason to believe Rainier wouldn’t behave similarly.
If I recall correctly, Duckster works on St. Helens and knows something about this. Anything to add?
I can see Popo’s plumes every morning from my roof terrace. A major pyroclastic event would probably eliminate the roof, terrace and everything below it. But I think the lahar flow maps put Puebla and the towns south of the mountain at much greater risk.
I’d be concerned for most of Costa Rica if Arenal/Poas/Irazu/etc. decided to explode.
Quito is pretty close to Cotopaxi. Ban~os is on the side of an active volcano, and is (or was) off-limits to Peace Corps workers.
In NZ, not just Auckland, but most of the major population centers of the North Island are at risk one way or another.
Lake Taupo is a supervolcano that erupts on an approximate 2000 year schedule, and last erupted in 181CE (lobbing rocks half way across the Pacific).
Whakaari (White Island) in the Bay of Plenty has been rumbling for years - if it goes spectacularly, Whakatane and Tauranga would be wiped out by the subsequent tsunami.
Why do you think I now live in the (geologically boring) UK 
Si
The entire eastern US?
Could there be a volcano in Southern California?
Is earthquake country also potentially volcano country?
They’ll be fine as long as Tommy Lee Jones is on the case.
No. Southern CA is located at a transform boundary, where the plates grind past each other. There is no real source of magma that takes part in the tectonic activity there.
Volcanoes like Kilauea, which is the most active on the planet and erupts almost constantly certainly damages property if the lava flows are to come near populated areas; however, it is not particularly dangerous to people. The flows don’t generally move fast enough to be able to catch you, and there is very little if any solid debris coming from the volcano. I guess if you got close enough you might be at risk for breathing in some fairly nasty gases, or falling into the lava…but that would be primarily due to your own stupidity.
OTOH, volcanoes like Vesuvius and Pinatubo erupt very infrequently and with huge columns/clouds of ash and rock and gases- called pyroclastic flows, mentioned by a few others. There is some lava but it is so thick it doesn’t really even flow. By far the most dangerous thing with volcanoes like these are these pyroclastic flows. They are not always easily predicted, they travel so fast nobody would be able to escape; they literally suffocate, incinerate, and bury you in one fell swoop.
All the cities along the Cascade Range in Washington and Oregon are at some level of risk from volcanoes. Most folks think of Mount St. Helens (now erupting for more than two and a half years), Mt. Rainier and Mt. Hood, yet most of the volcanoes stretching from British Columbia to northern California have the potential to erupt.
As Cervaise points out, the Seattle metro area is within the shadow of Mt. Rainier. The massive amount of glacial ice and snow is just sitting there, ready to be turned into a series of lahars that will practically remove Tacoma from the planet when it next erupts.
Mount St. Helens is still erupting, having started its latest episode in September 2004. Yeah, it’s not in the news but that’s probably because there’s no air show for the TV crowd. The volume of activity is way down from the big news period during the first six months of current activity, but don’t let that fool you. The USGS has been doing constant assessments of the activity. Their latest assessment says they now expect Mount St. Helens to remain in the current phase for some time. The volcano’s flanks are not inflating nor deflating, yet tens of cubic meters of magma continues to surface every second building the new domes. This means the volcano’s food supply is not coming from the suspected pool several kilometers below the surface but from much deeper. The earthquake activity is subdued but that’s probably because the magma has a clean and greasy channel to the surface.
Mt. Hood periodically shows up in the news when an earthquake strikes in the vicinity. It’s potential is similar to Mt. Rainier with lahars, but not of the same magnitude.
The biggest concern outside of those mentioned is the Three Sisters area east of Salem. The USGS was gearing up its monitoring of the Three Sisters volcanoes when Mount St. Helens began its latest happy dance. That’s because the research was seriously indicating a very large uplift of the entire area. Satellite photos were showing the entire area looked like a gigantic bullseye of uplift.
You can find a decent overview here —> Volcanic hazards with regard to siting nuclear-power plants in the Pacific Northwest
Most of the volcanoes in the Cascade Range are stratovolcanoes, the most dangerous type of volcanoes. According to the USGS:
Source: USGS: Volcano Hazards Program Glossary
Think of the Hawaiian magma as molasses. It flows but that’s about it. On the other hand, stratovolcanoes in the Cascade Range have a much higher silica content and produce magma similar to thick fudge. It doesn’t flow well. Instead, it gums up the works until the pressure from within becomes so great until all fucking hell breaks loose in massive eruptions.
Those eruptions blow the ejecta over a wide area. Add to it the lahars and the greatest threats are from the ash raining downwind and the lahars plugging up drainage channels. Mount St. Helens may not pose a risk to any nearby city, but if there is enough lahar material, it could reduce the flow of the Columbia River enough to cause considerable concern to Portland. The 1980 eruption raised the riverbed some 40 feet in places.
Given a choice to live in earthquake country (like California), Tornado Alley, or hurricaine land, I’ll take volcano country any day. I’ve lived in all of the above and find volcano country so much safer in the near-term as well as long-term.
You are forgetting the Mammoth Lakes area.
The only real danger Tokyo would have to a volcano would be from any earthquakes associated with it.
I lived in Kagoshima for five months back in the early 80s and saw some really beautiful eruptions of smoke and gasses.
Unless said volcano were to disrupt certain containment mechanisms, thereby releasing the occupants of Monster Island. That would be bad.
Located in the Sierras, Mammoth is two hundred miles from Southern California.
To be fair it could cause some problems for the Owens river which is a water source for the Los Angeles area
Actually I believe the most active volcano is in the African rift zone, in the show Planet Earth they mention it had molten lava on the surface for over 100 years. Kilauea is just one of the most active. While Hilo isn’t to big a massive eruption of Kilauea could cause the great crack to finally collapse into the ocean and doing it’s best to wipe out every single city on the Pacific rim with a massive tsunami. Although that’s just collateral damage, not damage from the volcano itself.
Honolulu is a big city and the island of Oahu is known for its post-erosional eruptions like Diamond Head, Koko Head, Punchbowl and others. In fact during the 50s there was some evidence for an eruption occuring off shore of Kaena point. Strange gasses and some pumice floating to the surface. Presumably one of these post-erosional eruptions could pop up anywhere on the island. Needless to say such an eruption would be devastating to the city.
It’s not overdue. A lot of sites like to say it blows every 600,000 years and the last eruption was 640,000 years ago, but the math doesn’t work.
There have been three known eruptions: 2.1 million years ago, 1.3 million years ago, and 640,000 years ago. The interval between the first two was approximately 800,000 years, and the next interval was 660,000. Besides the fact that two intervals is not enough to establish a pattern, the average interval comes out 730,000 years. How one can get an average of 600,000 when the smallest interval is 660,000 is beyond me.