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MSH80_bulge_on_north_side_04-27-80.jpg A "bulge" developed on the north side of Mount St. Helens as magma pushed up within the peak. Angle and slope-distance measurements to the bulge indicated it was growing at a rate of up to five feet (1.5 meters) per day. By May 17, part of the volcano's north side had been pushed upwards and outwards over 450 feet (135 meters). The view is from the northeast.
USGS Photograph taken on April 27, 1980, by Peter Lipman.
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MSH81_USGS_scientists_put_targets_on_dome_05-12-81.jpg Two USGS scientists (left middle) install targets and prism reflectors on Mount St. Helens dome.
USGS Photograph taken on May 12, 1981, by Lyn Topinka.
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MSH81_USGS_scientists_measure_radial_crack_base_dome_05-12-81.jpg The U.S. Geological Survey established both periodic and continuous 24-hour
monitoring programs at Mount St. Helens to study and predict eruptions. In this
slide, geologists used a steel tape to measure the distance across a crack on the
crater floor. Widening of cracks was an indication that magma was rising and
deforming the area, leading to an eruption. These cracks were generally
radial to the dome, like spokes of a wheel.
USGS Photograph taken on May 12, 1981, by Lyn Topinka.
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MSH81_USGS_scientists_measure_thrust_fault_05-12-81.jpg Two USGS scientists measure thrust fault at base of Mount St. Helens' dome.
USGS Photograph taken on May 12, 1981, by Lyn Topinka.
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MSH85_yellow_rock_05-28-81.jpg Yellow Rock station.
Yellow Rock's history spans back to mid-1981 when it was used for a variety of studies, including gas monitoring (fumarole), a magnetometer, a tiltmeter, and a seismic station.
USGS Photograph taken on May 28, 1981, by Terry Leighley, Scandia Labs.
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MSH85_yellow_rock_station_05-28-81.jpg Yellow Rock station.
Yellow Rock's history spans back to mid-1981 when it was used for a variety of studies, including gas monitoring (fumarole), a magnetometer, a tiltmeter, and a seismic station.
USGS Photograph taken on May 28, 1981, by Terry Leighley, Scandia Labs.
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MSH85_yellow_rock_station_05-28-81.jpg Hydrogen probe, Yellow Rock.
Yellow Rock's history spans back to mid-1981 when it was used for a variety of studies, including gas monitoring (fumarole), a magnetometer, a tiltmeter, and a seismic station.
USGS Photograph taken on May 28, 1981, by Terry Leighley, Scandia Labs.
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MSH81_installing_seismic_station_base_dome_08-04-81.jpg Geologists install a seismic station near the dome. The U.S. Geological Survey, in conjunction with the University of Washington, maintained seismic stations at Mount St. Helens. An increase in seismicity (earthquakes) was often the first precursor to an approaching eruption.
USGS Photograph taken on August 4, 1981, by Gene Iwatsubo.
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MSH81_monitoring_dome_crater_floor_08-22-81.jpg Monitoring the dome from the crater floor, north of the dome -- summer.
USGS Photograph taken on October 22, 1981, by Lyn Topinka.
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MSH81_collecting_gas_samples_base_dome_09-24-81.jpg USGS geologists collect gas samples around the dome. Samples were gathered from vents on the dome and crater floor, and were used to monitor changes in chemical composition. Additionally, sulfur dioxide gas was measured from a specially-equipped airplane before, during, and after eruptions to determine "emission rates" for the volcano. During eruptions, emission rates typically increased to 5 to 10 times their pre-eruptive value.
USGS Photograph taken on September 24, 1981, by Thomas J. Casadevall.
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MSH81_USGS_scientists_on_harrys_ridge_10-31-81.jpg USGS Scientists take deformation measurements from Harry's Ridge, located 5 miles (8 kilometers) north of Mount St. Helens.
USGS Photograph taken on October 31, 1981, by Lyn Topinka.
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MSH82_leveling_slope_changes_crater_floor_05-82.jpg Geologists did precise leveling to measure changes in the slope of the crater floor, due to moving magma. Changes in slope was also measured electronically by tiltmeters. Tiltmeters allowed 24-hour monitoring as the information was telemetered back to CVO. Other instruments such as displacement meters for measuring cracks, seismometers for measuring earthquakes, gas sensors for measuring gas concentrations, and magnetometers for measuring the magnetic field, were also used for 24-hour monitoring. Spirit Lake is visible in the background in this image.
USGS Photograph taken in May 1982, by Holly Martinson.
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MSH82_camera_barrel_base_dome_08-17-82.jpg Fifty-five gallon barrel drum used as a time-lapse camera mount, set up on the crater floor at the south side of the dome. Drum was easy to transport to the site, filled with dome rock for ballast, and camera installed and turned on. At the end of the day the camera and top case were retrieved. Barrel was covered by dome rock shortly after.
USGS Photograph taken August 17, 1982, by Lyn Topinka.
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MSH82_USGS_scientists_EDM_to_dome_08-17-82.jpg USGS scientists take EDM measurements to Mount St. Helens' growing lava dome.
USGS Photograph taken on September 17, 1982, by Lyn Topinka.
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MSH83_monitoring_dome_crater_floor_03-22-83.jpg Monitoring the dome from the crater floor, north of the dome -- winter.
USGS Photograph taken on March 22, 1983, by Lyn Topinka.
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MSH83_harrys_ridge_09-15-83.jpg In addition to monitoring stations within Mount St. Helens' crater, the U.S. Geological Survey also maintained a network of monitoring stations around the base of the volcano. Angle and distance measurements to the volcano's flanks were taken periodically to watch for any deformation similar to the 1980 bulge. Pictured here is the station Harry's Ridge, 5 miles north of Mount St. Helens' crater, with a USGS scientist setting up a theodolite.
USGS Photograph taken in September 15, 1983, by Lyn Topinka.
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MSH83_USGS_scientists_COSPEC_on_SugarBowl_10-21-83.jpg USGS scientists use a COSPEC (correlation spectrometer), to measure sulfur-dioxide gases being emitted from the dome. Setup on Sugar Bowl, located on the northwest flank of Mount St. Helens.
USGS Photograph taken on October 21, 1983, by Lyn Topinka.
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MSH84_harrys_ridge_and_st_helens_03-22-84.jpg In addition to monitoring stations within Mount St. Helens' crater, the U.S. Geological Survey also maintained a network of monitoring stations around the base of the volcano. Angle and distance measurements to the volcano's flanks were taken periodically to watch for any deformation similar to the 1980 bulge. Pictured here is the station Harry's Ridge, 5 miles north of Mount St. Helens' crater.
USGS Photograph taken on March 22, 1984, by Lyn Topinka.
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MSH84_USGS_scientists_survey_the_dome_05-26-84.jpg U.S. Geological Survey geologists use a theodolite and EDM (Electronic Distance Meter) to measure angles and slope-distances to the lava dome. Changes in these angles and distances are used to calculate "deformation rates". An increase in deformation rates is an indication that magma is slowly entering the dome. In the early 1980s deformation rates often reached 30 feet per hour (10 meters/hour) as magma rose and the dome expanded before extrusion started. During the winter months, the instrument stations often had to be dug out of the snow before measurements could be made.
USGS Photograph taken on May 26, 1984, by Lyn Topinka.
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MSH84_measuring_magnetic_field_in_crater_06-18-84.jpg Geologists measured the strength of the magnetic field surrounding the dome. The strength of the field increased as the dome cooled and magnetic minerals formed. During the eruptions the strength usually changed rapidly as magma heated and deformed the dome.
USGS Photograph taken on June 18, 1984, by Lyn Topinka.
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MSH85_USGS_scientists_deformation_top_of_dome_05-17-85.jpg USGS scientists make deformation measurements from top of the dome.
USGS Photograph taken on May 17, 1985, by David Wieprecht.
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MSH86_guacamole_tower_crater_dome_04-20-86.jpg Mount St. Helens crater and dome with the Guacamole Reflector Tower.
USGS photograph taken on April 20, 1986, by Lyn Topinka.
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MSH88_deformation_monitoring_top_dome_04-18-88.jpg In 1983, the U.S. Geological Survey extended both its periodic and its 24-hour monitoring programs to the top of Mount St. Helens' dome. In this aerial view, three geologists (middle bottom) were busy taking measurements to determine deformation rates
USGS Photograph taken in April 18, 1988, by Lyn Topinka.
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MSH89_outerflanks_monitoring_station_05-15-89.jpg In addition to monitoring stations within Mount St. Helens' crater, the U.S. Geological Survey also maintained a network of monitoring stations around the base of the volcano. Angle and distance measurements to the volcano's flanks were taken periodically to watch for any deformation similar to the 1980 bulge. Pictured here is an instrument station northeast of the volcano.
USGS Photograph taken in May 15, 1989, by Lyn Topinka.
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Hydrology
MSH80_cross_section_survey_upper_pine_creek_10-09-80.jpg USGS hydrologists measure the cross section at Upper Pine Creek. Mount St. Helens steams in the background.
USGS Photograph taken on October 9, 1980, by Lyn Topinka.
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MSH80_pine_creek_cross_section_10-09-80.jpg USGS hydrologist on rod at cross section along Pine Creek.
USGS Photograph taken on October 9, 1980, by Lyn Topinka.
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MSH80_pine_creek_bridge_remnant_10-24-80.jpg Remains of the bridge crossing the Pine Creek. Note USGS Hydrologist holding rod for cross section survey.
USGS Photograph taken on October 24, 1980, by Lyn Topinka.
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MSH81_pine_creek_bridge_remnant_after_storm_03-16-81.jpg Remains of the bridge crossing the Pine Creek. The original bridge was taken out during the mudflows of May 18, 1980. The banks were further eroded during the first major floods of 1981. Compare with image above. Note USGS Hydrologist holding rod for cross section survey.
USGS Photograph taken on March 16, 1981, by Lyn Topinka.
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MSH81_USGS_hydrologists_measure_erosion_06-26-81.jpg U.S. Geological Survey hydrologists measured changes in erosion along
the stream channels affected by the May 18, 1980 eruption.
These measurements were used to study the erosion processes and to
estimate the severity of the sedimentation problem. The view here
is along the Muddy River drainage, approximately one mile (1.5 kilometers)
southeast of the volcano's base. Rod person (lower left) and
instrument persons (upper right) give scale.
USGS Photograph taken on June 26, 1981, by Lyn Topinka.
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MSH81_spirit_lake_USGS_water_quality_boat_09-16-81.jpg USGS hydrologists (in boat, yellow circle) sample Spirit Lake for water quality, one year after the May 18, 1980 eruption of Mount St. Helens.
USGS Photograph taken on September 16, 1981, by Lyn Topinka.
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MSH81_sediment_sampling_hwy-99_12-06-81.jpg Sediment sampling, Highway 99 Bridge.
USGS Photograph taken on December 6, 1981, by Lyn Topinka.
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MSH82_coldwater_lake_early_warning_gage_10-01-82.jpg One major concern to people living downstream of Mount St. Helens was a breakout of any of the impounded lakes, such as Coldwater or Castle Lakes, due to the instability of the debris dams blocking them. Flood waters from a breakout could be more catastrophic than the lahars of May 18, 1980. Gages, such as this Early Warning Gage on Coldwater Lake, were installed at lakes and streams surrounding the volcano. These gages continuously monitored changes in water levels. Major increases or decreases in levels trigger warnings which are telemetered to the U.S. Geological Survey's Cascades Volcano Observatory in Vancouver.
USGS Photograph taken on October 1, 1982, by Lyn Topinka.
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MSH82_sediment_sampling_toutle_at_tower_road_12-12-82.jpg USGS hydrologists sample sediment moving down the Toutle River. View at Tower Road.
USGS Photograph taken on December 12, 1982, by Lyn Topinka.
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MSH85_USGS_hydrologists_sample_sediment_04-27-85.jpg Hydrologists measured stream discharge and took water samples to determine how much sediment is suspended in the stream and how much sediment is moving along the streambed.
USGS Photograph taken on April 27, 1985, by Lyn Topinka.
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MSH86_USGS_scientist_stability_experiment_08-86.jpg USGS Researcher, Dr. Richard Iverson, conducting debris flow stability experiment.
USGS Photograph taken in August 1986, by Lyn Topinka.
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