Impacts on School Resilience Caused by the M7 November 30, 2018 Anchorage Earthquake

Date: 4/26/2019

Time: 06:00 PM

Room: Grand Ballroom

The M7 2018 Anchorage earthquake caused damage to Anchorage and Matanuska-Susitna (Mat-Su) Valley schools, resulting in many remaining closed for a week or more for cleanup and repairs. Most damage was to suspended ceilings and the lights, heating and piping in and above ceilings. Schools were typically built to comply with seismic design codes instituted after the M9.2 1964 earthquake, and limited structural damage was observed. We compare observed damage to the spectral accelerations and peak ground velocity estimated and measured near several schools. Two schools in Eagle River, and one in Big Lake, suffered structural damage significant enough to close them for the rest of the school year. Structural damage to the gymnasium at an additional Mat-Su school caused closure. Observed structural damage was to reinforced masonry and concrete. Many older schools are wood-frame, and suffered no apparent structural damage. Non-structural damage to ceilings caused school closures for up to one week in Anchorage and up to two weeks in the Mat-Su Valley.

Many schools were in session at the time of the earthquake, and despite ceiling damage and falling of ceiling tiles, books and supplies (heavy furniture was anchored), both school districts reported very few injuries. Statements by the school districts, media reports, and field interviews with administrators indicate that along with structural performance, preparedness measures, including regular “Drop, Cover and Hold On” drills, were responsible for the low number of injuries. The combination of life-safety structural performance, anchoring of heavy furnishings, and student preparedness and drills to practice protective action appears to have protected students. If districts want to reduce lost instructional time, however, more attention must be paid to ensuring nonstructural components such as ceilings have adequate seismic design, and that older schools are seismically evaluated and strengthened or replaced if needed.

Presenting Author: John Thornley

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