High resolution multicomponent seismic data were collected to investigate the seismological effects of fluids, fracturing, and fine structures in Phanerozoic strata of a potash mining region in central Saskatchewan, Canada. The mining horizon is near the top of salts in the Prairie Evaporite Formation, at about 1 km depth. Field acquisition parameters were adjusted to record high, frequency data with as much offset as possible. This involved: 1. the use of 1/8 kg and 2 kg charge sizes, 2. single 3-component geophones buried every 4 m, 3. shot points every 16 m, and 4. spread lengths of 480-960 m. A total of 4.8 km of multicomponent surface seismic data were acquired. The smaller charge size proved satisfactory for producing frequencies up to 200 Hz without saturating the recording with ground roll generated in the 100 m of glacial till in this area. The increased vertical resolution in the P-wave seismic data sharpens previously mapped lithologic boundaries, and edges to mound structures below the Prairie Evaporite. Shear wave surface seismic data is unknown from this area until now. Despite roughly 100 m of glacial till, shear wave and PS reflections are visible on the raw field records for both charge sizes. Ray tracing and 2D elastic finite difference modeling confirm the field observation of very slow shear wave speeds in the till. The Vp/vs ratio in this near-surface deposit is 5.5.
|Number of pages||4|
|Publication status||Published - jan. 1 2018|
|Event||1994 Society of Exploration Geophysicists Annual Meeting, SEG 1994 - Los Angeles, United States|
Duration: okt. 23 1994 → okt. 28 1994
|Other||1994 Society of Exploration Geophysicists Annual Meeting, SEG 1994|
|Period||10/23/94 → 10/28/94|
ASJC Scopus subject areas