Since the enormous earthquake in Japan that crumbled homes and cracked streets and the subsequent tsunami that wiped out towns, we at Alpha Structural have provided a time-line of earthquakes that have happened on the East Asian Coast of the Pacific Rim that has affected Southern California and visa versa.
The US West Coast, Japan, Alaska, Canada, Phillippines all comprise the northern part of the Pacific Rim. The Pacific Rim also continues all the way down to lower South America as well. It has extremely heavy inter-related seismic activity spanning around the entire rim that has caused severe damage to all countries that are connected by this rim. All these countries that are connected have been experiencing earthquake and tsunami threats and actual disasters for centuries.
In 1968, an 8.2 magnitude earthquake rocked Japan and destroyed hundreds of homes. The tsunami destroyed parts of the coast line, sank ships and damaged coastal homes. This was the earthquake of Honshu Island Near Misawa, Japan. Three years later in 1971, the 6.6 magnitude Sylmar earthquake sent a shockwave through the San Fernando Valley. It destroyed homes, hospitals and freeways. The damage was estimated at over $500 million dollars and took almost two years to repair the damage.
In January 1994, the 6.4 magnitude earthquake devastated the San Fernando Valley. The “Northridge Quake” destroyed thousands of home, destroyed freeways and damaged many bridges. The estimated cost of building and road damage was over $20 billion dollars – a record for California. Coincidentally, almost exactly a year later, a 6.8 magnitude earthquake which claimed the lives of over 6,000 happened on Awaji Island of Japan. It destroyed thousands of homes, bridges, freeways and large buildings. It caused approximately ten trillion yen in damage, which comes out to approximately $102.5 billion (US) in damage.
In September 1999, a 7.6 magnitude quake jolted Taiwan. This quake caused more landslides and structural failures than usual and ended up destroying thousands of homes and injuring over 10,000. The quake was a disaster. Oddly enough almost exactly one month later, a large 7.1 magnitude earthquake shook Southern California in the Mojave Desert. The quake was felt in the Los Angeles County, Las Vegas and Carson City. Although the casualty rate was very low on this quake, you can see a pattern of quakes between Eastern Asia’s Coast and the West Coast. The Pacific Rim has constant seismic activity and it’s quakes that span across an entire ocean have a very important correlation with each other. It is no coincidence that so many quakes happen right after another even when they are an entire ocean apart.
The common denominator that resulted in the extensive damage in both Southern California, Japan and Taiwan is that the structures and homes do not have earthquake retrofitting or foundation bolting. That is why so many homes crumble and cave in on themselves, why bridges fall and walls topple over. That is why hillside homes fall down the hills they are built on and it is why foundations crumble, crack and fail.
It is imperative that Southern California home owners have a qualified hillside and foundation specialist (like Alpha Structural’s team) inspect your home to ensure your foundation is in top shape. The average earthquake retrofit job is around $5,000 – a very small investment considering the valuable trade-off of protecting your home and primary investment.