USGS/Cascades Volcano Observatory, Vancouver, Washington
Video and Television Surveillance Monitoring Systems
Miller and Hoblitt, 1981, Volcano Monitoring by Closed-Circuit Television:
IN: Lipman and Mullineaux (eds.), The 1980 Eruptions of Mount St. Helens,
Washington: USGS Professional Paper 1250
Visual monitoring of Mount St. Helens volcano by closed-circuit television
allows eruptive events to be observed as they occur and an immediate evaluation
of potential hazards to be made. Use of the remotely controlled TV system also
reduces risks to personnel during eruptions by eliminating the need for close-in
observers on the north side of the volcano, and reduces to need for continuous
observation from aircraft.
Visual monitoring of Mount St. Helens volcano by closed-circuit television was
started in July 1980. The TV system consists of a remotely controlled video
camera situated on a ridge 9 kilometers north of Mount St. Helens, a microwave
repeater station west of the volcano, and viewing and recording equipment at the
Emergency Coordination Center (ECC) in Vancouver, Washington. There, the
picture is monitored during daylight hours by personnel of the U.S.Geological
Survey and the U.S.Forest Service. The TV surveillance system was installed to
allow direct visual monitoring of the volcano by personnel in Vancouver, to
reduce or eliminate hazards to ground observers during eruptions, and to reduce
the need for, and thereby the cost of, continuous observation from aircraft. A
system was selected, assembled, and installed near the volcano by July 15, and
became fully operational on July 20.
Advantages of the TV surveillance system, in addition to those mentioned above
are as follows:
- Eruptive events can be observed as they occur and their potential
dangers can be immediately assessed.
- The volcano can be examined at any time during daylight hours except
during periods of cloudy weather (at night, incandescent events can be observed).
- The video system permits events at the volcano (for example, eruption
plumes, avalanches) to be correlated with other monitoring data received by
telemetry at the Emergency Coordination Center in Vancouver.
- Weather conditions can be viewed each morning prior to planning the
day's activities at and near the volcano.
- The video signal can be recorded on magnetic tape to provide a record of
events for subsequent scientific studies.
The video system provides a sharp, live color picture of the mountain and has
proven to ba a valuable monitoring tool for hazards response and in planning
daily operations. During periods of good weather in July and August, the system
was operated for as much as 13 hours per day. Electrical power is adequate for
about 65 minutes of pan, tilt, and zoom functions per day, which permits viewers
in Vancouver to investigate the state of the volcano each morning and to look
for changes that may have occurred overnight. ...
The system is used regularly to examine fluctuations in gas emission, avalanche
frequency, local wind conditions, blowing ash in potential work areas, and
eruptive events. The system is also useful for briefing scientists and public
officials without visiting the volcano.
Furukawa, Murray, and McGee, 1992,
Video Surveillance of Active Volcanoes Using Slow-Scan Television:
IN: Ewert and Swanson, (eds.), 1992, Monitoring
Volcanoes: Techniques and Strategies Used by the Staff of the
Cascades Volcano Observatory, 1980-1990: USGS Bulletin 1966
Video monitoring using slow-scan television has proved to be a valuable
monitoring tool at Mount St. Helens. The system provides a permanent video
record of events at the volcano and is also an important aid in planning field
logistics and operations. Such a system is particularly valuable at remote
volcanoes, where continuous observations are otherwise no feasible.
Video monitoring of Mount St. Helens volcano using slow-scan television (SSTV)
began on September 4, 1987. The system consisted of a video camera, a scan
converter, a radio transmitter, and a power system, all located on a ridge 8.5
kilometers (5 miles)
north of Mount St. Helens; a radio repeater on a high point west of
the volcano; and a scan converter, video monitor, and recording equipment at the
Cascades Volcano Observatory (CVO) in Vancouver, Washington.
After several months of operation, the system was modified to turn off a night
and back on again in the morning in order to conserve power. A later
enhancement included the capability to remotely control various other functions,
such as zoom and pan.
Video monitoring of active volcanoes has several attractive benefits.
there is the potential to significantly reduce the cost of monitoring a volcano.
Adverse weather conditions as well as steam and dust conditions can be observed
and considered before planning daily field activities.
- Second, the need for
aircraft observation flights is reduced.
- Third, a reliable video system can
significantly reduce hazards to field personnel during periods prior to and
during eruptive activity, by supplementing on-site observations of field
personnel. Remote variable-power zoom can allow observers to remain a safe
distance from the activity.
- Fourth, video information available during daylight
hours is easily correlated with other telemetered monitoring data to assess
At night, an SSTV monitoring system could utilize an
infrared camera for monitoring hot spots. Or a video cassette recorder (VCR)
could be connected at the output of the video camera in parallel with the output
of the scan converter and triggered to turn on in response to either a control
signal from a base station or a signal from a monitoring device in the field
such as a seismometer or a trip wire, in order to continuously record events
such as eruption plumes, debris avalanches, or lahars for subsequent detailed
analysis. It is even possible to design a transportable SSTV system that could
be rapidly deployed at volcanoes threatening to erupt. Finally, video
information can be stored on magnetic tape for future analysis.
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02/27/98, Lyn Topinka