Optimum Seismic, Inc.
February 2023 Newsletter
Thousands of Californians may be at risk of death and injury in major quakes
Ali Sahabi, GEC
Principal,
Optimum Seismic, Inc.
How many soft-story apartment buildings will still be standing after a major earthquake strikes your community? It’s an important question — because the first step to overcoming danger is to recognize and size up the threat.
That’s why Optimum Seismic teamed up recently with Esri, a leading mapping company, to develop interactive maps showing where thousands of potentially vulnerable soft-story apartment buildings are located in cities large and small throughout Southern California.
What we found was startling: There may be as many as 60,000 locations in California with these older multi-story apartment buildings in cities without retrofit ordinances, representing nearly 600,000 units. If 30% of those structures need retrofitting, that is almost 180,000 units.
Assuming an average of 2.5 residents per unit based on census estimates, that represents 450,000 people potentially at risk of death, injury or homelessness when a major earthquake strikes near their homes. That’s a risk too important to ignore
7.8 quake kills 11,000 people in Turkey, Syria
A powerful magnitude 7.8 earthquake rocked wide swaths of Turkey and neighboring Syria on Monday, killing more than 11,000 people and injuring thousands more as it toppled thousands of buildings and trapped residents under mounds of rubble.
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Quake the size of Turkey’s 7.8 in SoCal would be devastating
Three weeks of nearly nonstop rain in California caused as much as $30 billion in damage statewide – much less than a major earthquake would bring locally.
A 7.5 quake on the Puente Hills fault from southeast LA to downtown, could kill 18,000, and leave 750,000 homeless amid $250 billion in damages.
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Adaptive reuse popular among apartment owners
Adaptive reuse is turning rundown buildings into ravishing apartments. A report by RentCafe shows the nationwide trend. These reinvented spaces were more popular from 2020 to 2021,the study says. Adaptive reuse grew by 25% while new apartments grew by 10%.
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How big is the largest possible earthquake?
The amount of energy released in an earthquake is controlled by how much of the crust breaks. We’re not likely to see a magnitude 10. While a quake larger than a 9.5 could occur, it would require an enormous chunk of crust to break all at once, and there aren’t many places on Earth where that could happen.
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Retrofits give freeways a clean bill of health
A new analysis produced by University of Washington researchers concluded the great majority of bridges in the inland I-5 corridor would remain standing after a major 9.0 earthquake, thanks to seismic retrofits of vulnerable structures.
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Huge warning after 7.9 quake strikes tourist area
Tsunami warnings were issued recently in Indonesia following a major earthquake in the Banda Sea which could be felt as far as Australia. The magnitude 7.9 earthquake, which struck last month, led to seismologists issuing evacuation orders.
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Navy closes docks at risk of earthquake damage
Four dry docks the Navy uses to overhaul nuclear submarines were closed after the service found they are at risk for earthquake damage. The dry docks are still certified to overhaul nuclear submarines, but the Navy has decided to keep the dry docks empty pending further investigation.
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Economic Impacts of Major Quakes on Businesses Topic of Webinar
Experts To Discuss Preventing Serious Earthquake Damage
Economic impacts of major earthquakes in California such as those that devastated Turkey and Syria will be discussed by a panel of experts on the next Resilience Advantage webinar from 10 to 11:30 a.m. on Tuesday, Feb. 21.
The human toll of the recent earthquakes is staggering. More than 11,000 are confirmed dead and some 50,000 injured in the massive 7.8 quake – the largest to hit the region in more than 100 years — as of Wednesday, Feb 8. Thousands of buildings collapsed and continuing aftershocks left many without shelter in freezing weather.
Economic impacts of the earthquakes are projected to be severe for the two countries that were already suffering difficult economic conditions. Although the full extent of the devastation is not known, experts say recovery from this large an earthquake can take years and even decades.
“The earthquake had a rupture length of more than 300km (186 miles), said an expert in the field, Professor Paul Martin Mai. “Villages and towns are destroyed, economies are affected, the life infrastructure – gas, electricity, water pipelines – will be disrupted. The impact on the local population and economy will be massive because it’s such a big earthquake that affected a large area,” the academic from the Earth Science and Engineering department at King Abdullah University of Science and Technology in Saudi Arabia told CNA’s Asia Now.
“These earthquakes are a wakeup call for our nation,” says Evan Reis, Executive Director of the U.S. Resiliency Council. “Reducing the potential for such severe loss of life and damage to our economy is imperative.”
