This United States Geological Survey (USGS) on-line publication covers the volcanic history of the Lassen Volcanic National Park area in California. This includes information about identifying hazardous volcanic processes in Lassen (ash falls, basaltic lava flows) and studying non-eruptive hazards (rockfalls, landslides). Details about the prospect of future eruptions and monitoring for volcanoes, ... Full description.

This resource describes the nature of pressure surfaces and explains the dynamic processes associated with the eruption model. It contains a movie depicting a cross-sectional view of an explosively erupting volcano, typical of a so-called Plinian eruption. Additionally, there is a link to a computer program, which allows the user to construct a diverse group of volcanic landforms through the simulation ... Full description.

In 1986 the eruption of Kilauea Volcano changed from the episodic fountaining of lava and gas at Pu`u O`o cone every few weeks to the continuous outpouring of lava from a new vent only 3 kilometers away. The volcano began releasing a large, steady supply of sulfur dioxide gas into the atmosphere. During the episodic activity, enough time had elapsed between fountaining episodes for the prevailing ... Full description.

This site introduces the several methods geologists use to monitor changes in a volcano. These methods assist in forecasting intrusions and eruptions and consist of ground movements, seismicity, gas geochemistry, and geology. As a result of this lesson, students will realize that eruptions have precursor activities, recognize patterns in volcano behavior, and interpret graphical data. This site includes ... Full description.

This web page describes the lahars that swept down the Drift River Valley during the 1989-90 eruption of Redoubt Volcano, Alaska, and the testing of a new experimental detection and warning system designed to track lahars and debris flows and to give warning to people downstream. In this case, an oil-storage facility in the Cook Inlet area was at risk. The seismometers used (acoustic-flow monitors) ... Full description.

The distribution of earthquakes and volcanoes around the world confirmed the theory of plate tectonics first proposed by Wegener. These phenomena also help categorize plate boundaries into three different types: convergent, divergent, and transform. Full description.

Until recently, people living in a volcano's shadow had little help in predicting eruptions. In the past 300 years, volcanic eruptions, most of them unexpected, have killed more than 250,000 people. In 2000, experts estimated that 500 million people were living in areas at risk from catastrophic volcanic eruptions. This illustrated essay describes the strides scientists have made in eruption forecasting ... Full description.

This interactive resource adapted from the National Park Service explains the difference between explosive or effusive (lava pours from a vent onto the ground) volcanic eruptions, and describes the hazards associated with each type of eruption. Full description.

Information given in this United States Geological Survey (USGS) publication includes a description of volcano landslides, how they are generated, and their effects on surrounding areas. Case studies of specific volcano landslides are linked from this page, including Mt. St. Helens, Otake in Japan, Huila in Columbia, Mt. Rainier, and Casita in Nicaragua. Full description.

This online simulator lets students observe what happens to volcanic eruptions as the silica content of the magma changes. Operating a slider changes the percentage of silica, and the display shows the rock type, type of eruption, and type of volcanic edifice. It also displays temperature, pressure, viscosity of the lava, and seismic activity. A brief tutorial describes how to use the simulator and ... Full description.