Thousands of Earthquakes Rattle California in the Last Week, Raises Concerns for Soft Story Structures
After suffering two massive earthquakes over the fourth of July holiday weekend, California has experienced a new earthquake roughly every minute after.
Since that 6.4 temblor – the first quake to rock Ridgecrest, CA on July 4th— there have been over 5,400 small earthquakes in the area.
The US Geological Survey released new video showing the persistent earthquakes in the area, which have spanned from last Thursday to Monday.
The 6.4 and the 7.1 earthquakes of Ridgecrest have left the affected areas in shambles, and rattled residents throughout southern California.
As residents have started to gather survival necessities for the next “Big One,” it’s important to take every precaution necessary to prepare your home and loved ones for a large earthquake.
Kenneth O’Dell, president of the Structural Engineers Association of California, is using last week’s massive quakes to remind California residents of the importance of earthquake retrofitting.
The last time a major earthquake hit a densely populated area was the ‘94 Northridge quake which resulted in dozens of deaths and 16 apartment building collapses.
While Los Angeles, and other counties in Southern California, have since implemented soft story retrofitting laws – which require owners of vulnerable apartment building to have these properties retrofitted, O’Dell says there are still tens of thousands of soft story structures that remain throughout the Los Angeles county.
“I don’t want to frighten people,” O’Dell told NBC News. “But I think it’s important to be transparent. This is a real issue.”
In fact, O’Dell estimates that half a million people probably call these soft story structures home.
A soft story structure is a common apartment building in Los Angeles, designed with the units located above a parking lot that’s tucked underneath. Given that the parking lot of these structures lack the strength to withstand a large earthquake, these buildings are known as soft stories. We saw the destruction of these types of buildings in Los Angeles with 6.7 temblor that struck the San Fernando Valley in 1994.
These types of buildings were typically constructed before 1978 — before earthquake-conscious construction was taken into consideration and effect.
Because the parking lot of these structures bare the entire weight of the building, the posts that support the structure are typically too weak, which means “they buckle” in a quake.
Soft story retrofits typically implement additional support to these ground floors by adding beams between columns. This helps to create a framing support system that can withstand the back-and-forth and side-to-side shaking of an earthquake.
Darla A. Baker / The Californian
In addition to soft story buildings in the LA region, it’s equally as important to take the proper seismic precautions if you own an older home in the area.
Homes that were likewise built before the 1970s lack modern structural reinforcements to their foundation. Without popper earthquake retrofitting, these houses will slide off their foundations in the event of a large earthquake which will make them uninhabitable and dangerous to those who live there.
If you own an older home or building in California, chances are the property is lacking modern seismic reinforcements. Earthquake retrofitting will protect your property from damage and/or destruction during a large earthquake and ensure the safety of those who reside there.
Julian De La Torre is an expert in Los Angeles foundation inspection, foundation contractors, earthquake retrofitting, and foundation repair. Julian’s company, Julian Construction, has inspected over 15,000 structures, working with engineering firms and local departments of building & safety. The company has done more foundation repair and earthquake retrofitting in Los Angeles than any other company in the area over the last five years.
