February 3, 2017
Gordon Hoekstra’s article in the February 2nd Vancouver Sun entitled: “U.S. expert warns B.C. of potential earthquake risk to wood-frame homes” is misleading in some aspects and requires a response.
First, extensive on-the-ground research in Japan post-quake revealed a very different picture than presented in this article. Following the magnitude 7.3 Kumamoto Japan quake, the Japan 2X4 Homebuilders’ Association physically surveyed 2,940 modern wood-frame residences in the region. 97.3% exhibited no or very light cosmetic damage.
After the historic 2011 magnitude 9.0 Tohoku quake, survey results of 20,895 modern wood-frame homes indicated that 94% suffered no damage or cosmetic damage only, 5% were damaged but repairable, and 1% destroyed. However, of the 1% destroyed, none were due to seismic force. It was tsunami or fire from adjacent buildings that were the causes. Therefore, none of the wood-frame houses inspected in two seismic events suffered collapse due to earthquake motion.
These recent seismic events in Japan have validated the structural integrity of modern wood construction and effectiveness of applicable codes. In fact, the Japanese Ministry of Infrastructure, Land and Transport (MLIT) commissioned post-mortem studies and concluded that no amendments to current codes were required.
Japan, like many jurisdictions, has progressively improved its building codes to the point that modern wood construction is demonstrably safe and preferred by consumers as a result.
Michael Giroux, Canadian Wood Council
Derek Nighbor, Forest Products Association of Canada
Rick Jeffery, Coast Forest Products Association
Susan Yurkovich, Council of Forest Industries