Volcanic Hummock
Volcano Terms and Definition

Volcano Book
Volcano & Earthquake DK Eyewitness Books
Eyewitness Books provide an in-depth, comprehensive look at their subjects with a unique integration of words and pictures.

Lava Flows and Lava Tubes
40-minute video uses spectacular and unusual footage of erupting volcanoes from Hawaii and around the world to explain the features found in many of our volcanic national parks and monuments, and to show how they form. It presents up-to-date scientific ideas about lava flows: how they move, how they change, and how they create lava tubes

Fire Mountain: The Eruption and Rebirth of Mount St. Helens
Two hundred and thirty square miles leveled in moments Five hundred and forty million tons of ash and volcanic rock exploded twelve miles high One cubic mile of earth blasted from the crest of one of the world's most beautiful snowcapped domes Captured in rare and spectacular aerial photography and survivor's own words and pictures, witness the terrifying fury of the worst volcanic disaster in American history

Ring of Fire - IMAX
The Closest You'll Ever Get to a Volcano Originally filmed in IMAX Ring of Fire takes you heart stopping close to the great circle of volcanoes and seismic activity that rings the Pacific Ocean. This film has been seen by millions of people. The story of these immense volcanic forces and the half a billion people that coexist with them every day around the fiery boundary of the Pacific Rim

Savage Earth

Waves of Destruction
Out of the Inferno
Restless Planet
Hell's Crust
From the legendary fury of Mt. Vesuvius to the devastating convulsions of Kobe, Japan, Savage Earth tells the stories of these great natural disasters

A large hummock on the 1980 landslide deposit from Mount St. Helens stands above a wetland area (foreground) that lies between other hummocks. These hummocks once formed part of the volcano's summit, which was removed by an enormous landslide on 18 May 1980. The landslide scattered the summit rocks widely in the North Fork Toutle River valley.

are rounded or conical mounds within a volcanic landslide or debris avalanche deposit. Hummocks contain a wide range of rock debris, reflecting the variation of deposits that previously formed the flanks of the volcano. Some hummocks contain huge intact blocks tens to hundreds of meters in diameter. Some of the original layering of lava flows and other deposits can be seen in these large hummocks, but most of the large rock fragments are thoroughly shattered. In other hummocks the rock debris is thoroughly mixed as if the material had been in a blender and thoroughly mixed together.

Lavas exposed in hummock
This hummock contains mostly dacite erupted from Mount St. Helens about 2,500 years ago. The dark rocks capping the hummock are from lava flows erupted between 2,200 and 1,700 years ago. The same layering of the two types of lavas is found in the crater of Mount St. Helens, located about 7 km away (see next photograph).

Same lavas exposed in crater
These same lavas are exposed in a gully within the crater of Mount St. Helens. The light-colored rock is part of a dacite lava dome erupted about 2,500 years ago. The darker rocks are basaltic lava flows erupted sometime between 2,200 and 1,700 years ago.

Lavas exposed in hummock
This small hummock consists of andesite and basalt lava flows that were erupted on Mount St. Helens sometime between about 2,200 and 500 years ago.  In this hummock, most of the original volcanic layers were not preserved during transport of the landslide.

Same lavas exposed in crater
The same andesite and basalt lavas are visible in the upper part of the crater walls of Mount St. Helens. These rocks are identical to those found in the hummock above. The andesite and basalt flows are younger than the white-colored dacite lava dome. The red colors are a result of iron that oxidized within the lava while still very hot.

Hummock of young dacite rocks
This gray to pink-colored hummock is made up of dacite rocks from the Goat Rocks and summit domes, which erupted in the early 1800s and between 500 and 200 years ago, respectively. The hummock consists mainly of dacite lava and pyroclastic-flow deposits that shed from the lava domes during their growth.

Same dacite rocks on former summit of Mount St. Helens
View of the lava dome that capped the top of Mount St. Helens before the 18 May 1980 eruption. The pink to gray rocks of the summit dome seen prior to 1980 are the same rocks preserved in the hummock above. Both the Goat Rocks and summit domes were removed by the debris avalanche.

Volcanic eruptions are the clear and dramatic expression of dynamic processes going on in planet Earth. The author, one of the most profound specialists in the field of volcanology, explains in a concise and easy to understand manner the basics and most recent findings in the field of volcanology.

NOVA - In the Path of a Killer Volcano
The scientists who remain behind- and see some astonishing footage of the world's largest volcanic eruption in 80 years. Local tribes people were the first to see the signs. "There was a flash of light from the sky"

National Geographic - Volcano
The most dazzling but destructive natural force on earth. Massive volcanic eruption can turn day into night, releasing the power of an atomic blast, spewing toxic avalanches of lava, gas, and ash. National Geographic Video transports you to some of the world's most notorious volcanoes

National Geographic's Restless Earth Collection
Asteroids Deadly Impact Volcano Nature's Fury. The devastating powers of earthquakes, hurricanes, tornadoes, volcanoes and other earth-shattering forces of nature in dramatic scenes of destruction and inspiring human courage captured by the acclaimed filmmakers of National Geographic

Super volcano - It's Under Yellowstone. And It's Overdue

A subterranean sea of molten lava that scientists are sure will burst through the Earth's crust it's just a question of when. And if the resulting super-volcanic eruption is anything like the last one on earth which plunged the world into darkness for six years, tipped us into the last Ice Age

Volcano Glossary



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