Why are people still risking their lives to get close to active volcanoes?

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In summary, A pyroclastic flow from Mount Unzen, which erupted Monday, June 3, 1991, killed 43 people, many of whom were too close to the volcano.
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Pyroclastic flows contain a high-density mix of hot lava blocks, pumice, ash and volcanic gas. They move at very high speed down volcanic slopes, typically following valleys. Most pyroclastic flows consist of two parts: a lower (basal) flow of coarse fragments that moves along the ground, and a turbulent cloud of ash that rises above the basal flow. Ash may fall from this cloud over a wide area downwind from the pyroclastic flow.
https://www.usgs.gov/programs/VHP/pyroclastic-flows-move-fast-and-destroy-everything-their-path
With rock fragments ranging in size from ash to boulders that travel across the ground at speeds typically greater than 80 km per hour (50 mph), pyroclastic flowsknock down, shatter, bury or carry away nearly all objects and structures in their path. The extreme temperatures of rocks and gas inside pyroclastic flows, generally between 200°C and 700°C (390-1300°F), can ignite fires and melt snow and ice.

Pyroclastic flows vary considerably in size and speed, but even relatively small flows that move less than 5 km (3 mi) from a volcano can destroy buildings, forests, and farmland. On the margins of pyroclastic flows, death and serious injury to people and animals may result from burns and inhalation of hot ash and gases.

Pyroclastic flows generally follow valleys or other low-lying areas and, depending on the volume of rock debris carried by the flow, they can deposit layers of loose rock fragments to depths ranging from less than one meter to more than 200 m (up to about 700 ft).

A pyroclastic flow from Mount Unzen, which erupted Monday, June 3, 1991, killed 43 people, many of whom were too close to the volcano.
Mount Unzen (雲仙岳, Unzen-dake) is an active volcanic group of several overlapping stratovolcanoes, near the city of Shimabara, Nagasaki on the island of Kyushu, Japan's southernmost main island.
https://en.wikipedia.org/wiki/Mount_Unzen

https://en.wikipedia.org/wiki/Katia_and_Maurice_Krafft
Catherine Joséphine "Katia" Krafft (née Conrad; April 17, 1942 – June 3, 1991) and her husband, Maurice Paul Krafft (March 25, 1946 – June 3, 1991), were French volcanologists who died in a pyroclastic flow on Mount Unzen, in Japan, on June 3, 1991.

https://en.wikipedia.org/wiki/Katia_and_Maurice_Krafft#Mount_Unzen_eruption_and_death
On June 3, 1991, at around 4pm local time, Mount Unzen erupted, forming pyroclastic flows that rushed down its slopes, killing 37 people, including the Kraffts and fellow volcanologist Harry Glicken.
https://apnews.com/article/dec80c065dcb59f2e77c3193daeb7264
https://apnews.com/article/fdc407fb854da02eca942b3f0b80e772
The Geological Survey hired Glicken in 1980 to monitor Mount St. Helens from a trailer on a ridge 5.7 miles northwest of the volcano. After working six consecutive days, he was relieved by his friend and mentor, David Johnston, the elder Glicken said.

Johnston was on duty at 8:32 a.m. May 18, 1980, when Mount St. Helens unleashed a catastrophic sideways blast of hot gas and ash. Moments before he died, Johnston yelled into his radio to Geological Survey officials: ″Vancouver, Vancouver, this is it 3/8″
https://en.wikipedia.org/wiki/Harry_Glicken
 
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The Geological Survey hired Glicken in 1980 to monitor Mount St. Helens from a trailer on a ridge 5.7 miles northwest of the volcano. After working six consecutive days, he was relieved by his friend and mentor, David Johnston, the elder Glicken said.

Johnston was on duty at 8:32 a.m. May 18, 1980, when Mount St. Helens unleashed a catastrophic sideways blast of hot gas and ash. Moments before he died, Johnston yelled into his radio to Geological Survey officials: ″Vancouver, Vancouver, this is it 3/8″
About a year and a half before Mt. St. Helens erupted, a friend of mine and I were on the mountain. About Jan. 2, 1979, we were attempting a winter climb of this mountain. At the time, the temperatures were very cold, dropping to an estimated 5 deg. F. during the night. Because we got to the mountain late at night we camped at Spirit Lake. Also, because it was so cold, we had a late start the following morning and made it only to a feature known as the Sugar Bowl, a small, dome-shaped vent the next day. During that night, the temperatures warmed up a bit, rising all the way up to about 32 deg. F. When we finally set out in earnest the second morning, the snow was rock hard, but crampons gave us an excellent grip. Unfortunately for us, the warming temperatures caused the low valley clouds to rise up and merge with the high clouds, so by the time we got to about 8300' we were socked in and had used up all our red-flagged wands. Discretion being the better part of valor, we decided to call it, and headed back to the car. I didn't mind so much, as I had climbed the mountain about five years before that, on a beautiful summer day.
 
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In 1902, a pyroclastic flow from Mt Pelee engulfed the town of St. Pierre on the island of Martinique in the Caribbean. The superheated cloud killed basically everyone in the city, approximately 28,000 people.
https://en.wikipedia.org/wiki/1902_eruption_of_Mount_Pelée
 
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The Unzen images are incredible.

 
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Something of a coincidence relative to this thread, but I watched a documentary a couple nights ago about an eruption on White Island (AKA Whacaari) offshore from New Zealand's North Island. There was a regular tourist service that took visitors out to the island to look at the acid lake in the crater. On 9 Dec. 2019, the volcano erupted while tourists from one boat were still on the island. Either the pyroclastic flow or escaping steam eventually caused the deaths of 20 visitors to the island. Some of those who survived had to endure months of hospitalization for their burns.
 
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Mark44 said:
Something of a coincidence relative to this thread, but I watched a documentary a couple nights ago about an eruption on White Island (AKA Whacaari) offshore from New Zealand's North Island. There was a regular tourist service that took visitors out to the island to look at the acid lake in the crater. On 9 Dec. 2019, the volcano erupted while tourists from one boat were still on the island. Either the pyroclastic flow or escaping steam eventually caused the deaths of 20 visitors to the island. Some of those who survived had to endure months of hospitalization for their burns.
I remember the news reports. I went back and watched a documentary, possibly the same one. The guys who went back and saved lives were made of stern stuff.
 
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Mark44 said:
On 9 Dec. 2019, the volcano erupted while tourists from one boat were still on the island. Either the pyroclastic flow or escaping steam eventually caused the deaths of 20 visitors to the island.
What is sad about that event is the knowledge, as expressed by a tour guide, that an eruption was very likely. One of the visitors, Krystal Browitt, recorded a guide saying that the volcano was at Level 2 and heading to Level 3 (Level 3 = eruption), yet they headed to the edge of the crater! The Level 2 warning was in place for two weeks, and a warning had been issued on 25 November, 2019, by NZ Volcano Monitoring Authority advising a risk of likely eruption. The cruise ship company did not inform visitors of the risk, but clear the tour guide knew, or should have known, the risk.

Stephanie Browitt survived and had to endure more than 3 years of treatment for severe burns over 70% her body. Her father Paul survived a trip to the mainland, but succumbed to his injuries shortly afterward. Stephanie's sister, Krystal, died on the island. The trip was a spur of the moment activity, a day trip from a cruise the family took in part to celebrate Krystal's 21st birthday.

The victims were covered in ash and pelleted by rocks falling on them, as well as burned by hot steam. One survivor described deposition of hot crystals on his head and body, so hot ash and steam reached the people as they fled.

Twenty-two people died and another 25 people were badly injured.

Surely, the NZ authorities should have prohibited people on the island, but the tour boat company and cruise ship line should have warned their customers of the risk, and folks should not have been allowed near the crater. There were apparently no shelters on the island, or protective equipment made available.

In the case of the Kraffts and Harry Glicken on Unzen, they also did not have protective suits, or even a protective covering (aluminized mylar or carbon fiber sheet).
https://www.thinknsa.com/thermal/carbon-armour-silvers-11-oz-aluminized-opf-blend-ripstop-50-jacket
https://www.thinknsa.com/thermal/ca...1-oz-aluminized-opf-blend-ripstop-deluxe-hood
 
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1. What is a pyroclastic flow?

A pyroclastic flow is a fast-moving mixture of hot gas, ash, and volcanic rocks that can reach temperatures between 200-700°C. It is often associated with explosive volcanic eruptions and can travel at speeds of up to 700 km/h.

2. How are pyroclastic flows formed?

Pyroclastic flows are formed when a volcano erupts explosively, sending hot gas, ash, and volcanic rocks into the air. These materials then collapse and flow down the sides of the volcano due to gravity.

3. What are the dangers of pyroclastic flows?

Pyroclastic flows are extremely dangerous due to their high temperatures and speed. They can destroy everything in their path, including buildings, trees, and even people. In addition, they can also cause ash fall, which can be hazardous to human health and can damage crops and infrastructure.

4. Can pyroclastic flows be predicted?

While scientists can monitor volcanic activity and provide warnings about potential eruptions, it is difficult to predict when and where pyroclastic flows will occur. They can change direction and speed quickly, making it challenging to accurately predict their movements.

5. How can people protect themselves from pyroclastic flows?

The best way to protect oneself from pyroclastic flows is to evacuate the area as soon as possible when a volcano is showing signs of eruption. It is important to follow evacuation orders and have a designated safe location in case of an emergency. Wearing protective gear, such as masks and goggles, can also help reduce the impact of ash fall on the body.

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