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Rose Canyon earthquake could have 'devastating consequences' for San Diego

ROSE CANYON FAULT ZONE.png
Posted at 2:45 PM, Mar 04, 2020
and last updated 2020-03-05 17:50:50-05

SAN DIEGO (KGTV) — A scenario study on a 6.9-magnitude earthquake on the Rose Canyon fault zone paints a bleak picture, saying the San Diego region could suffer "devastating consequences."

The San Diego Earthquake Planning Scenario report examines the possible outcome of such an earthquake on the Rose Canyon fault line, which runs through the heart of downtown San Diego.

Under the scenario, the report concludes that a quake of this size could cause severe damage to buildings and emergency infrastructure and have "devastating consequences" on communities and the local economy.

RELATED: Examining San Diego's fault lines after Ridgecrest earthquake

"Damages will cause business interruptions across most economic sectors, estimated at $5.2 billion dollars in lost income throughout San Diego County," the report says. "Additionally, the earthquake will damage a large percentage of the housing stock in the San Diego region, further exacerbating housing affordability issues particularly for more vulnerable populations such as low income residents."

While the report is not a precise look at San Diego's seismic history or forecast of its future, it believes a 6.9M earthquake could potentially cause several scenarios:

  • $38 billion in damages, in which 120,000 buildings would suffer moderate to complete damage, 8,000 buildings would be beyond repair, and 36,000 households would be displaced;
  • Many older and more vulnerable buildings, including key City of San Diego buildings, could be severely damaged and suffer from partial to total collapse;
  • Coastal communities, stretching from La Jolla to Silver Strand, could be cut off from nearly all lifeline utilities and services, with some basic services being out for months; and
  • Loss of water pressure to certain communities could also impact response to any fires; and
  • Interstate 5 corridor would also be severely impacted, as potential roadway and bridge failures could present more challenges for first responders and residents

"Community and economic activity could be disrupted for years until the region’s housing stock, commercial and government facilities, and infrastructure are repaired or replaced," the report said.

RELATED: San Diego urged to make water line improvements ahead of future earthquakes

Based on its findings, the report recommended several steps moving forward to prepare San Diego for seismic activity, including:

  • A county-wide study of earthquake hazards;
  • Formation of a "seismic resilience" group to identify mitigation actions, priorities, and funding;
  • Local jurisdictions should compile vulnerable structures and develop a way to retrofit them;
  • Various agencies — including wasterwater utilities and emergency management agencies — identify and prioritize investments into needed upgrades; and
  • Updates to emergency response plans for local jurisdictions and increase public awareness

Ideally, the study envisions the San Diego region being retrofitted and ready for a major earthquake by 2050.

"With a better understanding of the severity of damage, challenges for repair, and the interconnectedness of structures and their lifelines, communities can take mitigation measures to aid in reducing the potential impacts to life and property and societal disruption in the region following future earthquakes. The conclusion of this report is a call to action in the form of a vision for a seismically resilient San Diego," the report says.

The report was prepared by a team of geoscience and structural engineering professionals and researchers led by San Diego Regional Chapter of the Earthquake Engineering Research Institute. Experts will discuss the findings during the National Earthquake Conference, being held in San Diego this week.

Read the full scenario report here.