The ice cap of Hoodoo Mountain volcano, northwestern British Columbia: estimates of shape and thickness from surface radar surveys

Abstract

Preliminary results from a multiple-traverse radar survey across an ice cap situated on top of Hoodoo Mountain, a Quaternary subglacial stratovolcano in northwestern British Columbia are presented. The project defined the shape of the ice sheet and mapped the subglacial summit region of the volcano. Four traverses, using low-frequency ice radar and higher frequency ground-penetrating radar units, provided traces of the ice base as well as shallow, finer scale, internal reflectors. GPS was used to locate survey lines and individual radar traces were time tagged to position. The ice cap has a relatively even thickness (120-150 m) across the summit region, with no evidence of a deep crater or caldera beneath. The minimum volume of ice is estimated at 3.2 km3. To more accurately gauge the potential for significant jökulhlaups at Hoodoo Mountain, additional work is necessary to define the nature and size of subglacial catchments basins.

Ground-penetrating radar mapping of Minoan volcanic deposits and the Late Bronze Age palaeotopography, Thera, Greece

“…Volcanic stratigraphy is particularly appropriate for study by GPR because the deposits are commonly thin and compositionally homogeneous, and they can be electrically resistive (Stasiuk & Russell 1994;Russell & Stasiuk 1997). The deposits on Thera are also particularly dry and situated well above the water table, which means that there will be little attenuation of the radar signal by pore or surface water.…”

“…The deposits on Thera are also particularly dry and situated well above the water table, which means that there will be little attenuation of the radar signal by pore or surface water. Previous studies by McCoy et al (1992), Stasiuk & Russell (1994), Gilbert et al (1996), Russell & Stasiuk (1997) and Russell et al (1998) have shown that GPR has tremendous potential for quantifying distributions, thicknesses and volumes of volcanic deposits, and perhaps can even be used to study facies variations within individual units.…”

“…The radar velocities or the dielectric properties of these deposits are generally not known a priori (e.g. Russell & Stasiuk 1997) and, therefore, an important first task is to estimate the radar velocity of the target deposit. For a well-exposed section, as found in the Phira quarry ( Fig.…”