Abstract

The Kipawa, Québec earthquake (mN5.2 OTT; mb4.5 pIDC) occurred on 1 January 2000 at 11:22:57 UT (6:22 EST). The epicenter (46.88°N 78.92°W) was beneath Lake Kipawa, approximately 10 km north of the town of Témiscaming, Québec. The earthquake was felt to distances exceeding 500 km. The “Felt Earthquake” form on the Geological Survey of Canada's Web pages received more than 450 submissions from more than 170 communities regarding this earthquake. The shaking was very strong for residents within 50 km of the epicenter (maximum intensity MM VI), and minor damage (fallen light objects, one broken ventilation pipe, and cracks in plaster) was reported. The seismograph station EEO (Eldee, Ontario), at a distance of 29 km, recorded a 0.023 g peak vertical acceleration, and a digital strong-motion unit operated by Hydro-Québec at 68 km distance recorded 0.014 g maximum horizontal acceleration. Twenty-three aftershocks were recorded, ranging from ML 1.1 to mN2.2. To supplement station EEO, two portable recorders and a digital strong-motion instrument were installed on 2 January 2000 at distances of 9 to 22 km from the epicenter of the main shock. Preliminary analysis of the main shock from P first motions and surface-wave modeling indicates thrust faulting on an east-west or northwest-southeast trending plane. A depth of 13–16 km is indicated by the regional and teleseismic body waves. The epicenter is within 15 km of that of the magnitude (MW) 6.1, 1935 Timiskaming earthquake and lies in a cluster of 76 earthquakes located since 1935. The area averages one magnitude 3 or greater earthquake every two years. There is an indication of a northwest-southeast elongation (parallel to the major faults of the Lake Timiskaming Graben), and focal mechanisms consistently show a northeast-dipping northwest-trending plane, which would be consistent with a fault outcropping under the Ottawa River and Lake Timiskaming.

You do not currently have access to this article.