Leech River Fault Array

Date: 4/24/2019

Time: 06:00 PM

Room: Grand Ballroom

The Leech River Fault is one of three major terrane bounding fault that runs through the southern tip of Vancouver Island, BC. The Survey Mountain Fault and San Juan Fault separate Wrangellia terrane to the north, from the Leech River schists to the south. The Leech River Fault separates the Eocene Metchosin basalts to the south from the Leech River schist to the north. It runs from Sombrio point on the western edge of Vancouver Island over seventy-five km eastward, through the waterfront of Victoria, BC, and presents a seismic hazard to the region. Recent studies suggest that the fault may have been active in the Quaternary, however it is unclear how much of a present day risk it presents. Previous studies have shown that seismic activity in the Victoria region lies within the large packages of terrain rocks, rather than on the pre-existing faults bounding them. To explore whether there is any small scale movement on the fault that may have not been recorded by the regional seismic network, ten instruments were deployed around the Victoria area to cover the eastern portion of the fault (approximately one-third the total fault length) and the subsurface expression of the fault, which dips to the northeast. This seismic array uses Geotech S-13 sensors with sample rate of 500 sps at a station spacing of 5-10 km to detect small, high-frequency events.

Presenting Author: Taimi L. Mulder

Authors