Eruptive Frequency and Hazard Prediction for the Garibaldi Volcanic Complex, British Columbia

Abstract

The Garibaldi Volcanic Complex is located in south-western British Columbia, Canada and forms a 25 km-wide belt of volcanic centres stretching from Mount Garibaldi, at the head of Howe Sound, north-west for ~140 km to Bridge River. The Complex is constructed on a series of metamorphosed intrusions of quartz diorite and granodiorite. This complex has been active from 1.3 Ma to as recent as 6670 years B. P. The purpose of this study is to both characterise and document the volcanic history of the Garibaldi volcanoes and attempt to constrain their eruptive nature and frequency, and thus potential hazards. This work includes: field sampling, petrological investigation of representative samples, and detailed examination and modelling of crystal populations and their patterns of zonation to determine magma-chamber processes. Magma recharge events, a common cause of volcanic eruptions, have been documented in several minerals across both belts through detailed microscopic study. Analysis of these profiles can provide important information on the repose periods of the Garibaldi volcanoes as well as the timescales between recharge and eruption. This data has the potential to significantly improve current eruption forecasting models.