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Natural Resources Canada > Earth Sciences Sector > Priorities > Geological Survey of Canada > Volcanoes of Canada
Volcanoes of Canada The Hoodoo Mountain project
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Figure 56. Hoodoo MountainHoodoo Mountain and its icecap, with the adjacent Iskut River valley in the foreground.
(Photo by M. Stasiuk (Geological Survey of Canada))
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In the summer of 1997 a group of university, GSC and industry scientists
spent 6 weeks camped at the edge of Hoodoo Mountain's summit
ice cap. The volcano (Figure 56)
is a flat-topped tuya, or subglacial volcano, although at
least some of its eruptions have occurred since the last ice
age. Most of its eruptions have produced lava flows from the
summit area, and it's safe to assume that any future activity
will happen beneath the summit ice and so is likely to cause
significant melting, flooding and mudflows.
| What potential threat of an eruption |
The volcano is flanked by Twin and Hoodoo glaciers, which drain into the
Iskut River (FIgure 57).
Relatively few people live in the area, but downstream on
the Iskut River there is an airstrip and a major mining and
mineral exploration camp. Further downstream, logging operations
use the river (Figure 58).
In addition, the Iskut is a major salmon spawning river. The
intent of the expedition was to determine the volume of water
on the volcano's summit which could be mobilized in the event
of an eruption, using ice-penetrating radar.
Figure 57. The Iskut River ValleyThe Iskut River valley. An eruption of Hoodoo Mountain would melt ice and could create mudflows in the Iskut River.
(Photo by M. Stasiuk (Geological Survey of Canada))
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Figure 58. Industry & wildlifeAlthough few people live near the Iskut River, it does support a range of wildlife such as salmon, as well as mining and logging operations.
(Photo by M. Stasiuk (Geological Survey of Canada))
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| Getting the equipment to the Base Camp |
The work began with the group departing from Stewart by airplane, heading
with all the equipment and supplies to the Iskut airstrip
(Figure 59). Once at the Iskut airstrip, we packed the equipment into a
net sling (Figure 60), which was carried by helicopter to the volcano summit and
our base camp location (Figure 61, Figure 62, and Figure 63).
The helicopter was the group's only means of transport off
the volcano, and also the only way to get new supplies. The
helicopter (and airstrip) was present because of mining and
mineral exploration operations in the area.
Figure 59. Packing the supplies & equipmentPacking the single-engine airplane with our supplies and equipment in Stewart, en route to the Iskut airstrip. Remarkably, we were able to fit it all in, with enough room left over for us.
(Photo by M. Stasiuk (Geological Survey of Canada))
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Figure 60. The net slingOn the Iskut airstrip, packing the net sling with supplies and equipment in preparation for transport to the volcano.
(Photo by M. Stasiuk (Geological Survey of Canada))
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Figure 61. View of the icecap margin, Hoodoo MountainView of the icecap margin from the helicopter during transport of the team and equipment from the Iskut airstrip to the summit. The base camp was set up in the dark area at the edge of the ice.
(Photo by M. Stasiuk (Geological Survey of Canada))
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Figure 62. Base campThe base camp consisted of a collection of tents on a surface of lava rubble.
(Photo by M. Stasiuk (Geological Survey of Canada))
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Figure 63. The helicopterThe helicopter bringing in a sling of supplies. It took 3 sling loads to get our camp to the summit. The weather held well enough to complete the move in a single day, although between sling loads we were treated to a thunderstorm - unfortunately our tents were among the last items to be transported.
(Photo by M. Stasiuk (Geological Survey of Canada))
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The group (Figure 64, Figure 65, Figure 66, Figure 67)
consisted of Mark Stasiuk (GSC), Alison Rust (UBC), Trevor
Page (U. Lancaster), Guy Cross (Golder Associates), Jeff Schmok
(Golder Associates), Kelly Russell (UBC), Ben Edwards (UBC),
Jim Nicholls (U. Calgary) and Catherine Hickson (GSC).
Figure 64. The TeamThe entire group, except for Catherine Hickson who joined the expedition a little later. From left to right: Mark Stasiuk, Alison Rust, Trevor Page, Guy Cross, Jeff Schmok, Kelly Russell, Ben Edwards and Jim Nicholls.
(Photo courtesy M. Stasiuk (Geological Survey of Canada))
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Figure 65. Base campLeft: Jim Nicholls (U. Calgary), with Kelly Russell (UBC). Most of the tents were set up beside the ice, where they could be anchored solidly to avoid being blown away by high winds.
(Photo by M. Stasiuk (Geological Survey of Canada))
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Figure 66. Base camp kitchenThe kitchen area. Not exactly elegant, but it got the job done. From left to right, Jeff Schmok, Trevor Page, Guy Cross, Ben Edwards and Alison Rust.
(Photo by M. Stasiuk (Geological Survey of Canada))
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Figure 67. Catherine Hickson at the Iskut airstrip, preparing to join the expedition.
(Photo by Kelly Russell (UBC))
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Over the next 6 weeks, we criss-crossed the 3 km diameter icecap surface
(Figure 68), precisely locating our paths using GPS (Figure 69).
Behind us we towed a sled holding the radar instrument (Figure 70
and FIgure 71).
Figure 68. Hoodoo Mountain aerialAerial view of the volcano and surrounding features.
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Figure 69. Topographic map, Hoodoo MountainTopographic map of the summit area, showing the extent of the ice in blue and the ice radar survey lines, located by GPS.
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Figure 70. Ice radar equipmentThe ice radar equipment. The batteries and digital oscilloscope, used to record the data, were towed in a plastic sled. Towed behind this were the radar antennae.
(Photo by Kelly Russell (UBC))
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Figure 71. A survey being performedA survey being performed. Left to right, Jim Nicholls, Alison Rust and Guy Cross.
(Photo by M. Stasiuk (Geological Survey of Canada))
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Figure 72. A radar profileA radar profile through the ice for a 1100 meter long traverse over the center of the icecap. The vertical axis shows depth in meters, which was calculated from the radar return times using the velocity of radar frequency light in ice. The base of the ice is defined by the relatively strong radar reflection at a depth of about 150 meters. Using such results, we were able to determine the volume of ice and the shape of the subglacial part of the volcano summit.
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Radar waves in the frequency 1-10 MHz are able to penetrate ice to
considerable depths, and the instrument essentially sends out
a radar pulse that bounces back from the base of the ice. By
measuring the time taken for the radar pulse to travel through
the ice, it's possible to calculate the ice thickness. This
is much like depth sounding in water using sonar (sound) waves,
or in rock using seismic waves, and the results look similar
(Figure 72).
The results of the expedition show that the ice forms an approximately
150 meter thick cap whose total volume is about 0.3 cubic
km. We continue to work on the results to determine the likely
impact on the surrounding environment of melting Hoodoo's
icecap.
Funding for the expedition was provided by a NSERC collaborative grant
to JK Russell, along with in-kind support from the GSC.
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