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Evaluation of Earthquake Scenarios for the Greater Montreal Area

Session: Recent Engineering Uses of National Seismic Hazard Models [Poster]

Type: Poster

Date: 4/22/2021

Presentation Time: 11:30 AM Pacific

Description: 

Damage to residential buildings, as well as economic and social impacts, were estimated for 6 earthquake scenarios in the vicinity of the Greater Montreal, Canada using the Hazus software. The Greater Montreal Area is the second largest agglomeration (4 millions, about 48% of the Quebec province) in Canada and is located in a moderately seismic region (PGA around 0.38g for a return period of 2475 years). Single family housing units represent 74% of the building stock and 90% of the 870'000+ documented houses are wooden frame structures. On the island of Montreal, these values are 56% and 81% respectively, due to the large number of duplexes and triplexes (35% of the total number of buildings) and a large number of unreinforced masonry buildings (18% of the building stock). The building exposure is estimated around 300 billions of Can$, the content accounting for 55% of the total. The influence of the soil conditions on the ground motion calculations is taken into account by using V_s30 data on a regular grid of 250m derived from various seismic surveys as well as boreholes and geological data. For the scenarios considered, extensive and complete damage levels represent 0.9 to 12% of the building stock on the island of Montreal depending on the selected scenarios; these numbers values range from 1.1 to 4.8% for off-island municipalities in the Greater Montreal Area. The total losses vary between 1 and 12% of the portfolio in the island of Montreal depending on the selected scenario. These percentages decrease to 0.02 à 0.07% for off-island municipalities, the non-structural damage accounting for 80% of the total damage on average. Debris generated by the damage vary between 0.8 to 8 millions tons, wood and brick materials representing around 65% of the total. The need of temporary shelters is of the order of 5 to 60 thousands, the number of people needing hospital care varies from few tens to thousands depending on the scenario and the time of occurrence of the earthquake. The next step is to estimate the average annualized seismic losses at the same spatial scale.

Presenting Author: Luc Chouinard

Student Presenter: No

Authors