Fourpeaked Mountain facts for kids
Quick facts for kids Fourpeaked Volcano |
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Fumaroles escape from Fourpeaked volcano through a fissure in Fourpeaked Glacier on 24 September 2006
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| Highest point | |
| Elevation | 6,903 ft (2,104 m) |
| Geography | |
AVO map showing the location of Fourpeaked Volcano
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| Location | Kenai Peninsula Borough, Alaska, U.S. |
| Parent range | Aleutian Range |
| Topo map | USGS Afognak |
| Geology | |
| Age of rock | > 10,000 years |
| Mountain type | Stratovolcano |
| Volcanic arc/belt | Aleutian Arc |
| Last eruption | September 2006 |
Fourpeaked Volcano is an active volcano in Alaska, a state in the United States. It's a special type of volcano called a stratovolcano, which means it's shaped like a cone and built up by many layers of hardened lava and ash. Most of Fourpeaked Volcano is covered by the Fourpeaked Glacier, a large sheet of ice.
The Alaska Volcano Observatory (AVO) keeps a close eye on Fourpeaked. They use a special system to warn people about volcanoes. For Fourpeaked, the AVO usually says it's at an "Aviation Alert Level Green" and "Volcanic-alert Level Normal." This means the volcano is quiet and not showing signs of erupting.
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When Did Fourpeaked Erupt?
Before September 17, 2006, Fourpeaked Volcano had been quiet for a very long time. It had been "sleeping" for over 10,000 years! This means it was a dormant volcano.
First Signs of Activity: September 2006
On September 17, 2006, something big happened. Pilots and other people saw two huge clouds of steam rising from Fourpeaked Volcano. These clouds were so large that they could be seen from Homer, a town far away across Cook Inlet.
Scientists from the USGS and the AVO quickly flew over the volcano. They found that a lot of volcanic gases were strongly escaping near the top of the mountain. Air samples confirmed these gases were indeed from the volcano. Because of this, the Alaska Volcano Observatory officially said that Fourpeaked was having an explosive eruption.
Monitoring the Volcano: September 2006
On September 20, 2006, the Alaska Volcano Observatory changed Fourpeaked's alert level. They moved it to "Yellow" on their color-coded system. This system is now called the Aviation Alert Level.
At this time, scientists started putting special equipment on the mountain to listen for earthquakes. They also began using planes and helicopters to watch the volcano closely.
AVO's Warning: September 2006
On September 25, 2006, the AVO gave a special warning. They said that Fourpeaked would probably erupt again soon. They shared some possible things that could happen:
- A small to medium eruption might happen. This could send ash clouds higher than 10 kilometers (about 33,000 feet) into the sky. Lava flows might also happen.
- The volcano might just calm down, and no eruption would occur.
- A very large eruption could happen. This would also send ash clouds higher than 10 kilometers and could cause ash to fall over a wide area.
Earthquake Swarm: October 2006
By October 3, 2006, the Alaska Volcano Observatory had set up another seismometer, which is a tool to detect earthquakes, near Fourpeaked. Soon after, they started to detect many small earthquakes. This is called an earthquake swarm. These small quakes continued off and on until the spring of 2007. Fourpeaked also kept releasing volcanic gases at the same rate as before.
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Increased Activity: February 2007
In February 2007, Fourpeaked started to show a small but clear increase in activity. On February 8 and 9, the AVO reported that three small explosions were recorded by their instruments. They also saw a possible large steam cloud from satellites.
On February 18, the AVO reported another swarm of 13 small earthquakes under Fourpeaked. The strongest one measured 1.8 on the Richter magnitude scale. A few days later, on February 23, scientists flew over the volcano again. They found that it was still releasing sulfur dioxide gas.
Small Explosions Continue: March 2007
In March 2007, the Alaska Volcano Observatory reported that "several small explosion signals" were detected overnight. These small explosions had started in February and continued until June. In June, Fourpeaked's alert level was lowered back to "Green," meaning it was quiet again.
