Volcano Topography and Volcanic Hazards: Topographic Characterization and Monitoring of Volcanoes

Mt. St. Helens

Photo of Mt. St. Helens from the collection of the Cascade Volcano Observatory.

The Players

The Motivation

Monitoring the topography of potentially hazardous volcanoes is important both for documenting past activity and recognizing the potential for future activity. Many volcanoes are capable of causing floods, mudflows, and landslides, as well as volcanic plumes and flows. Besides being life-threatening, all of these catastrophic events can cost agriculture, government, private property owners and industry millions of dollars. Volcanoes such as Mt. Saint Helens and Mt. Rainier are located near highly populated, urban areas. Mt. Saint Helens, once thought to be dormant, reawakened in 1980. Thus declaring it's hazard potential and proving that long term monitoring of Cascade volcanoes is necessary. In the past Mt. Rainier has produced enormous mud flows, some of which reached the Seattle-Tacoma metropolitan area. Topographic monitoring of summit areas could reveal pre-eruption indicators, such as; large scale tilts and bulges over active magma chambers, subsidence of glacial ice due to near-surface magma, or the appearance of a new crater or vent.

mud flow

Armero, Colombia was destroyed by mud flows on November 13, 1985. More than 23,000 people were killed when mud flows swept down from the erupting Nevado del Ruiz volcano. Photo from Cascade Volcano Observatory, by R.J. Janda.

The Research

Topography is an important parameter used to describe volcanic landforms. However, high precision methods for rapidly determining the complex topography of volcanoes, to the resolution necessary for remote monitoring and hazard prediction, have only recently emerged. Since the middle 1980's, a small group of scientists and engineers at NASA's Goddard Space Flight Center (GSFC) have been developing airborne and spaceborn laser altimeter methods for measurement of elevations of terrestrial surfaces, including volcanic landforms.

These technological developments have enabled scientists to gather very accurate topographical information for the study of several active and potentially hazardous volcanoes, including:

Mt. Saint Helens Mt. Saint Helens

This photo shows Mt. Saint Helens' mudflows triggered by the March 1982 eruption. Photo from the Casade Volcano Observatory, by Thomas Casadevall.

Mt. Saint Helens is located in the Cascade range, in Washington state. It's last major eruption occured in 1980; since then numerous smaller eruptions have occured. Topographic cross-sections of the summit region (including the dacite lava dome) have been aquired with airborn laser altimeter systems since 1987, with continuously improving reliability and accuracy. In September 1993, cross-sections of the Mt. Saint Helens' central dome were aquired with no more than a few tens of cm vertical error. This data can serve as the basis for continued monitoring of the changing topography of the dome as well as the entire edifice.

small Earth imageLink to NASA photos and topography model of the St. Helens dome.small Earth image

Mt. St. Adams Mt. Adams

Another member of the Cascade range in Washington, Mt. Adams has been inactive during historical times. Multiple topographical cross-sections of Mt. Adams were aquired during the airborne laser altimeter surveys of 1993. In contrast to more recently active Cascade volcanoes, Mt. Adams shows rather gradual slopes, with 80% of local slopes (i.e. on baselines < 10m) less than 60 degrees.

Photo from the collection of the Cascade Volcano Observatory.

Mt. Rainier Mt. Rainier

Mt. Rainier, which last erupted approximitly one hundred and fifty years ago, is also a member of the Cascade mountain range, close to the Seattle-Tacoma metropolitan area. As part of the airborne laser altimeter surveys of 1993, multiple topographic cross-sections of Mt. Rainier were aquired. Mt. Rainier is relatively steep; 80% of it's local slopes (i.e. on baselines < 10m) are less than 30 degrees. This slope curve suggests that Rainier is transitional between the long-period dormancy of Mt. Adams, and the recent eruptive activity of Mt. Saint Helens.

The laser altimetry, in combination with other methods, could provide the basis for characterizing changes in hazardous volcanoes in terms of their topographic characteristics. This approach has been adopted for a NASA-supported multi-year study of the topography of the summit region of Mt. Rainier,scheduled to commence in 1995.

small Earth imageCheck out these wire mesh topography plots of Mt. Rainier.small Earth image

Photo from the collection of the Cascade Volcano Observatory.

For a topographic comparison of Mt.SaintHelens, Mt.Adams and Mt.Rainier visit this page.

Skjaldbreidur, a classic lava shieldSkjaldbreidur

Located in Iceland, Skjaldbreidur is a classic lava shield. Skjaldbreidur will be monitored by RADARSTAT, an orbital remote sensor. RADARSTAT will aquire monthly SAR images of Skjaldbreidur, which will then be analyzed in an attempt to measure the spacial and areal changes associated with the volcano.

More information about Skjaldbreidur can be found here.

Photo by Ingiblorg Kaldal.


Pico is located in the Azores Islands, an island chain west of Spain in the Atlantic Ocean. Uncharacteristicly quiet during the past few decades, Pico last erupted in 1963. Pico makes up a significant portion of the island of Pico, and is reminiscent of the stratocones of the Pacific rim. However, Pico rises 7700 feet above sea level, and displays a summit region topographically more akin to an oceanic shield than to a pyroclastic stratocone. The work with Pico, done in collaboration with Prof. V. H. Forjaz of the University dos Azores and his colleagues, has focused on analyzing it's upper reaches using laser altimetry. Scientists have observed summit region local slopes consistently above 45 degrees with evidence for slump scars as well. The Shuttle Radar Laboratory imaged Pico in October 1994, and the NASA laser altimeter remote sensing mission to the Azores in September 1994 aquired 4 transects across the edifice, with 3 m horizontal sampling and sub-meter vertical precision.

small Earth image Don't miss these fabulous NASA aerial images and topography models of Pico and the Azores.small Earth image


Fogo, located in the Cape Verde Islands, is a major mid-Atlantic volcano which was last active in 1951. Fogo previously displayed a long period of semi-continuous eruptive activity between 1500 and 1761. Today, scientists are studying Fogo island with hopes of understanding the ongoing eruptive activity and the nature of any human hazards it might pose. A SPOT Pilot Project focusing on monitoring and documenting the results of the ongoing volcanic eruption of Fogo is imminent. In addition, efforts are afoot to overfly the Fogo volcano with NASA aircraft for the purpose of airborne laser topographic observations using either NASA airborne laser altimeter or SAR interferometer sensors. Data will also be used to guide field studies of the eruption, and as a basis for future volcano monitoring studies.

small Earth imageDon't miss these amazing

Related volcanology research:

Other interesting volcano pages:

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page created by:

  • Lisha McCormick
  • Goddard Space Flight Center
  • National Space Club Scholars
  • 7/27/95