Mount St. Helens

The eruption of Mt. St. Helens on May 18, 1980 did give significant warning before the actual large eruption took place. There was a period of a month and a half of unrest before the flank collapse and lateral blast events took place.

The unrest began being documented March 15, 1980, however it was not immediately recognized as possibly being a precursor to a volcanic event. The seismic events were first recognized as precursor activity on March 20th, 1980 with a magnitude 4.2 under the north flank of the volcano (Which also turned out to be the eruptive and failure point of the volcano on May 18).

For further and detailed readings on the precursor events before the triggered eruption please see related links for the Cascade Volcanoes Observatory.

The cryptodome on the side of Mount St. Helens was approximately 1,300 feet long, 65 feet wide, and 40 feet high. It was a large bulge caused by rising magma beneath the volcano before its 1980 eruption.

Dacite, a volcanic rock with about 65% silica. This amount of silica in dacite is a lot higher than the basalts of Hawaii which have less than 50% silica. The high silica content makes the magma "sticky" and can cause more pressure to build up. With so much pressure, eruptions from Mount St. Helens can be very violent like the famous 1980 eruption.

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Mount St. Helans is aproximatly 120km or 75 miles away from the pacific ocean.

No. Mount Bona in Alaska is the tallest volcano in the United States at 16,421 feet and Mount Rainier is the tallest in the continental U.S. at 14,441 feet. Mount St Helens is significantly shorter at 8,363 feet. Even before the 1980 eruption, Mount St Helens was 9,677 feet.

Ecological succession is an important theory in ecology that states recovery of flora and fauna is a slow predictable process that restores an evironment to its orginal state after some sort of severe destructive event. However, ecologists learedn by studying the aftermath of the Mount St. Helens eruption that the planet will recover much faster and in more unpredictable ways than originally believed.

Mount St. Helens, located in the Cascade Range in Washington state, experiences a temperate marine climate at lower elevations and alpine climate at higher elevations. Weather conditions on the mountain can change rapidly and are characterized by strong winds, heavy precipitation, and frequent cloud cover. Winters are typically cold and snowy, while summers are mild with cool temperatures.

The eruption of Mount St. Helens in 1980 led to significant short-term climate effects, including the release of ash and gases into the atmosphere that temporarily impacted local and regional weather patterns. The overall global climate impact of the eruption was minimal due to the relatively small amount of ash and gas released compared to larger volcanic events.

The cost of ash removal from the eruption of Mount St. Helens in 1980 was approximately $1.1 billion. This amount covered various expenses such as debris removal, infrastructure repairs, and reforestation efforts.

Mount St. Helens is currently in a state of volcanic quiescence, with no signs of imminent eruption. Monitoring stations are actively tracking the volcano's activity for any potential changes to provide early warning if it becomes restless again. The U.S. Geological Survey continues to keep a close eye on Mount St. Helens and surrounding areas for any signs of volcanic activity.

Mount St. Helens last erupted on May 18, 1980, making it around 41 years old since its most recent eruption. However, the actual age of the volcano itself is over 40,000 years old, with its first-known eruptive activity dating back to about 40,000 years ago.

Some birds that lived on Mount St. Helens before the eruption in 1980 included the northern spotted owl, northern goshawk, and varied thrush. These birds inhabited the diverse habitats of the mountain, ranging from forested areas to alpine meadows.

Mt. St. Helens has had several different styles of eruptions through its history. The types of eruptions vary from explosive to dome building.

The explosive history of Mt. St. Helens is relatively well known from the May 18, 1980 eruption that captured world attention at the time. The eruption style was typical of this volcano, pyroclastic flows and lahars were both generated. The flank collapse was more than likely a result of the earthquake under the flank at the time, and is believed to have been the trigger of the eruption itself.

Dome building eruptions have been the most common types of eruptions since the 1980 explosive eruption. There have been several lava domes generated since the summit eruption that generated the crater.

Although they have not been witnessed in historical time, Mt. St. Helens does have a history of passive lava eruptions out of flank vents. This type of eruption although it hasn't been witnessed in a rather long time, it is believed that these types of eruptions have been just as common if not more common than the explosive eruptions we have seen in historical times.

Mount St. Helens is located along the Cascadia Subduction Zone, where the Juan de Fuca Plate is subducting beneath the North American Plate. This subduction zone is a convergent plate boundary, resulting in the volcanic activity that built the mountain and led to its catastrophic eruption in 1980.

One surprising research finding about the aftermath of the eruptions of Mount St. Helens was the speed at which plant and animal life started to rebound and recolonize the devastated area. Scientists were amazed at how quickly ecosystems began to recover, with new plant growth appearing within weeks and new species of insects and animals returning within years. This rapid recovery challenged previous notions about the resilience of nature in the face of such catastrophic events.

The crater at Mount St. Helens is about 1.2 miles (1.9 km) in diameter. It was created during the catastrophic eruption in 1980, which also caused the summit of the mountain to collapse.

If you're talking about mt st Helens then it last erupted on 1st October 2004, but it is most notorious for its catastrophic eruption on 18th May 1980 at 8:32 am.

So about 7 years. =)

The 1980 eruption of Mount St. Helens did not produce lava flows. It was an explosive eruption that prudiced an ash plume and pyroclastic flows. Pyroclastic flows are avalanche-like masses of superheated ash, rock, and gas. Pyroclastic flows from the initial lateral plast reached as far as 19 miles. Ash blown high into the atmosphere was carried by the wind for thousands of miles.

Some of the immediate responses to the Mt St Helens eruption in 1980 were....

Mobilising helicopters to search and rescue those in the vicinity of the catastrophic blast.

People setting up emergency treatment in nearby towns as they were closer than having to go to the hospitals

Face masks were sent from the US when they all ran out. President Carter sent 2 million more over.

It was triggered by an earthquake measuring 5.1 on the Richter scale, caused an eruption, reducing the elevation of the mountain's summit from 9,677 ft (2,950 m) to 8,365 ft (2,550 m) and replacing it with a 1 mile (1.6 km) wide horseshoe-shaped crater. The earthquake was caused by a sudden surge of magma from the Earth's mantle. The debris avalanche was up to 0.7 cubic miles (2.9 km3) in volume.

Plug dome volcanoes typically eject viscous magma, which is known as rhyolite lava. This lava is thick and flows slowly, leading to the formation of steep-sided domes as it cools and hardens. As a result, plug dome volcanoes tend to have explosive eruptions due to the high pressure build-up of gas within the viscous magma.

No they are not alike. guess you would want to know the answer... ... Here is the reason, because different volcano have different forms of volcanoes and erupting. there are 2 different forms of volcanoes, 1 active and non active. There are also 2 forms of erupting methods too, 1 slow and fast. If the volcano erupts fast, you would not be able to escape it if you are near it. But if the volcano erupts slowly, you might have a chance to escape it even though you are near. (But slow or fast is not the thing that matters most nor if it is active or not. The most important thing is the ashes! If you breath in to much ashes, you would die or suffocate),this is just for eduacational use.

It can take several decades to centuries for Mount St. Helens to develop into a climax community. The speed of recovery depends on various factors, including the severity of the eruption, the availability of nearby vegetation and seeds, and the ecological processes involved in succession.