L.A. Earthquake Blog

Could An Unknown Fault Line Cause California's Next Big Earthquake?

It's just a matter of time before a major earthquake strikes Southern California, no question about it. Everyone knows this will happen, from the geologists and scientists at the USGS, to the journalists, our political officials, and everyone else in between. Spreading the message to the public and having them take action remains the biggest challenge. Not knowing when or where exactly this quake will hit is what keeps people from taking the necessary measures to prepare. And no one can really blame them, the ability to predict earthquakes is still in the works and knowing the exact location of where the epicenter will be can be elusive.

Fault Lines We Know, And Don't Know About

Take a look at the USGS's map of Southern California and you will see about dozens or more red lines running along the state that mark where faults are. Most of these fault lines are active and quite dangerous such as the San Andreas Fault because they can cause powerful earthquakes. But, just think about the faults that scientists haven't discovered yet -- the ones so deep or so out of our radar that could very well be the ones that could cause the "Big One."

A recent article published by the Natural Hazards Center in Boulder Colorado highlighted the danger that unknown or unmapped faults (also known as "blind" faults) pose to cities and towns in earthquake prone areas. The author, Erol Kalkan, detailed the events that led to the destructive 6.1 earthquake in Christchurch, New Zealand back in February 2011.That earthquake was the deadliest that the country had seen in 80 years.

According to Kalkan, 5 months before the earthquake in Christchurch occurred, a 7.1 magnitude earthquake struck some 20 miles west from the city, in the small town of Darfield. Scientist believe that the earthquake in Christchurch was one big aftershock from the Darfield earthquake. And get this: both of those earthquakes occurred in a previously unmapped fault line.

Last year, another earthquake struck in a previously unmapped fault: the one last August in Mineral, Virginia which caused alarm along the East Coast and damaged the Washington Monument. And back in January 2010, the 7.0 magnitude earthquake in Haiti was also generated by an unmapped fault.

Kalkan explained that scientist are constantly searching for new faults by using laser imaging technology. Californian geologists have used this technology as well, but the work continues. There are still faults out there that need to be mapped so that they can be monitored by scientists.

    (Photo: Aerial view of the San Andreas fault from 8500 feet altitude)

The Most Well-Known Fault in California

There are certainly many faults that still need to be identified, but why not take the time to write about the most well-known fault in the state, and probably the world: the San Andreas Fault. The San Andreas Fault is the longest fault in California. It runs 850 miles from the southern to the northern part of the state. It begins in Bombay Beach, on the Salton Sea some 168 miles south east of downtown Los Angeles, and it goes up north ending at the Mendocino Triple Junction, about 279 miles north of San Francisco, on the coast.

This deadly fault is responsible for most high profiles earthquakes that California has experienced, beginning with the most deadly earthquake in American history: the 1906 San Francisco earthquake, which measured between 7.7 to 8.25 magnitude. The Loma Prieta Earthquake in San Francisco in 1989 also occurred along the San Andreas Fault, it measured 6.9 in magnitude. 

 

                     (Photo: A crushed car after the 1989 Loma Prieta Earthquake in San Francisco.)

Another well-known area along the San Andreas Fault is Parkfield, in the central part of the state. Parkfield is the most monitored area of the world for earthquake activity, here is where a major earthquake strikes an average of every 22 years; a 6.0 magnitude quake struck there in 2004."The Parkfield Experiment" is a USGS program in Parkfield that is helping scientists understand how earthquakes work and how faults behave.

So Did The San Andreas Fault Cause The Northridge and Whittier Earthquakes?

Nope. The San Andreas fault did not cause the Northridge earthquake back in 1994. That earthquake occurred in a previously unmapped fault, now known as the Pico Thrust Fault.The 1989 Whittier earthquake, which caused a lot of damage in East Los Angeles also occurred on a previously unknown fault. So, I hope you're beginning to see a pattern here -- big quakes have happened where no one expected them happen. 

Many USGS scientist are predicting that the Big One may happen along the San Andreas fault -- more specifically, with an epicenter in the Salton Sea, where the fault originates. There is a lot of focus and attention placed on this prediction, which is justified. At the same time, the pattern of earthquakes that have been created by unmapped or blind faults is quite alarming and more needs to be done to identify potential hot spots for new earthquakes.

The earthquake in Darfield, New Zealand happened on a fault that led to the city of Christchurch. The two cities were connected by this fault, so when one big earthquake struck the smallest of them, no one paid that much attention. But the aftershock created by that quake did get the world's attention, and by then it was too late.

The lesson learned from Christchurch, New Zealand is to pay closer attention to those bigger quakes that tend to happen in more remote or far areas because you never know if that earthquake just happened on an unmapped fault that runs right beneath your home.

As always, preparedness is key. Store that water and food and stay safe.

Follow the L.A. Earthquake Blog on Twitter @LAEarthquakes

Unpreparedness in America: Who Will Help You?

 

No one can really say if we are living in a time of more news stories about natural disasters or if indeed we’re having more of them. The last decade was marked with hurricanes like Katrina and Rita and this decade started with major earthquakes in Haiti, Chile, New Zealand and Japan. In the US, tornado season started early this year and with quite a fury. What’s going on?

Global Warming?

In Japan, scientists see the culprit as global warming. At the earthquake memorial museum in Kobe where a major earthquake leveled the city in 1995, an exhibit plays a loop of video news footage of disasters that have struck different areas of the world since the 1980s. Hurricane Andrew is prominent and so are those California wildfires, volcano eruptions in places like the Philippines, etc. But most interestingly is a graph next to the huge plasma screen showing how the number of disasters has spiked since temperatures began to rise. The museum is funded by the Japanese government and no special interest seems to be behind the claim that weather is playing a role in all this.

Japan is well aware of its unfortunate geological position in the globe – sitting right where four major tectonic plates meet and making it the most earthquake–prone country in the world. This is why the government has spent a lot of money in educational programs to make its people aware of their place in the world. The government also continues to learn from past (and current) lessons and is working on improving emergency response time and investing more in preparedness. They know that more destruction from disasters will happen in the future, and they are constantly planning to minimize it.

The coast line along Tohoku that was hit by the March 11 tsunami following the 8.9 earthquake was not completely unprotected. In the past these same coasts had been hit by major tsunamis and the government took measures to protect its people from future tidal waves. People were asked to build their homes on higher ground and tall concrete walls were built along the shores to stop high waves from hitting the area, particularly in Iwate.

(Photo: A destroyed tsunami wall in Iwate Prefecture after the March 11, 2011 earthquake in Tohoku.)

Still, no one had predicted a tsunami like the one on March 11 – a monster tsunami that toppled concrete walls with waves as tall as 133 feet high. The end result was over 15,000 people dead, and 7,300 missing. But, the death toll would have been higher if the tsunami alert system had not worked as it did, helping to save thousands who moved to higher ground in a matter of minutes after the quake hit.

In America

Not all of the US has areas were natural disasters are likely to strike, but many cities and towns are vulnerable – rivers have flooded thousands of acres this year along the Mississippi, the Missouri River, and in North Dakota. Tornadoes have claimed over 500 lives and not in the traditional areas where they hit, like Kansas, but in unlikely places like Alabama. Fires are burning in the southwest in Arizona and New Mexico, right now threatening Los Alamos National Laboratory. Mother Nature has no boundaries.

FEMA has been quite busy this year providing assistance to survivors and businesses, but the time to take preparedness seriously is here. We can no longer be passive on how we see the weather or ignore the tectonic plates and faults that run beneath where we stand and where our homes are built. Our American cities, like New Orleans, have experienced the challenges that come when we expect the government to act quickly. As citizens, we must be proactive and not see storing water or food for emergencies as silly, but as important as picking up your kids from school.

The Cuts

Americans must also look at what cuts your local and federal governments are proposing. Cuts to emergency preparedness programs are not talked about as much, but they do happen. Preparedness and emergency response is not viewed or understood the way it should be by politicians. According to an article in the magazine Emergency Management, 33 cities did not receive funding for their emergency preparedness programs in 2011. Here is a portion of that article:

…although the regions may not feel the cuts immediately, the long-term impacts could be great. The UASI program — which began in 2003 with $100 million to strengthen regional preparedness in seven large metropolitan areas — was appropriated $662 million for fiscal ’11 to distribute among the designated 64 urban areas. The funding is about $170 million less than was available for fiscal year 2010, and has many UASI city representatives wondering how they will sustain their programs and capabilities long term.

Cuts are unavoidable in times of unbalanced budgets, but there are things that should be off the table, especially if public safety is a priority for politicians and anyone with legislative power. Emergency preparedness and other programs are investments in saving the lives of people in our communities and it’s something we all should be conscious of.

How prepared or unprepared for an emergency is your local government, do you know? And, how prepared are you?

First Person Account: How The Earthquake Was Felt In Tokyo

 

To my blog readers, I know this articles isn't about a quake in Los Angeles, but I wanted to share what I experienced yesterday in Tokyo. Cheers.

It’s been less than 24 hours since the 8.9 magnitude earthquake shook the Eastern coast of Japan. At 2:46 pm, local Japan time on Friday I was on the 7th floor of an office building in the busy district of Shibuya when the movement began. Since then, devastation closer to the epicenter plus aftershocks have kept most of us living in Tokyo on high alert.

The movement in Tokyo was slow at the beginning. I didn’t think much of it at first, but this seemed different than the quakes we are used to having — this time it wasn’t stopping, and worse, it was getting stronger. I rushed out of the office I was in and looked around as colleagues held the doors wondering why the quake wasn’t stopping.

The movement was back and forth and I couldn’t help wondering which walls would collapse first. After about a minute into the quake I rushed down the stairway. Many of the Japanese office tenants were making their way down as the shaking continued. Some walked very calmly. When we reached the first level and went outside the sidewalks were packed with people who had come to a standstill due to the quake. They were all looking up at the parade of buildings just moving back and forth. Most were calm, others were upset and holding on to one another.

I stood on the side of my building trying to reach relatives in the US to let them know I was OK, but the lines were already down. I used my iPhone to check the location of the quake via the USGS website and that’s when I first saw the big red square on the map, marking the epicenter — just off the coast of Sendai. "If the earthquake was felt so strong in Tokyo, how did the people 235 miles north of me, in Sendai, felt it?," I pondered.

We had another massive aftershock that was so strong we didn’t know if that was it. People didn’t know if to run or stay put, again we all looked around where we were standing and it struck me that if the glass began to fall down from the buildings around us, we could get badly injured. I walked down the block to the intersection of Meiji Street and Miyamasuzaka hoping to not be too close to tall buildings, but it made no difference — Tokyo is an ocean of tall buildings, some taller than others, but it’s almost impossible to not be beneath their shadows.

The people at Shibuya Station were paralyzed; I knew right away that those trains weren’t going anywhere. In case of an earthquake the trains and metro in Tokyo shut down and if I was going to get home all I could do was start walking. As I made my 5-mile walk from Shibuya to Jiyugaoka, I kept refreshing the news pages on my phone and trying to keep informed. Large pockets of Japanese people huddled around each other along sidewalks, looking at TV news on their cell phones.

There was no visible damage in Tokyo itself that I could see. It wasn't until later that I found out that a parking structure had collapsed in Machida and that other minor damage had taken place in the city. The real disaster had occurred in the Tohoku region.

When I got home I saw the live TV images of the tsunami waves swallowing anything on their path. All the Japanese TV channels were showing news of what had happened. There were tsunami advisories in Chinese, Portuguese, and English urging caution and for those living closer to the coast to move to higher ground.

We experienced many tremors and aftershocks throughout the rest of the afternoon and into the evening. Some of the aftershocks were 7.0 in magnitude at their epicenters. In Tokyo, these quakes felt less strong, but they were big enough to break dishes, mirrors, and cause other minor damage in my home.

My best estimate right now to a final death toll is between 1,000 to 3,000 dead, specially in the Sendai region. So far, the authorities have the toll at 200, with scores of people missing.

The shaking still continues as I write this first person account and we may have many more aftershocks well into April. So far this hasn’t been the earthquake Tokyo has been expecting for the past 25 years, that quake — the Tokai Earthquake — would devastate Shizuoka, Yokohama and Tokyo and it’s still 75 years overdue.

5.4 Magnitude Quake Shakes Southern California on July 7

A 5.4 magnitude quake shook Southern California on July 7, 2010. The quake was south west of Palm Springs on the Coyote Creek fault at 4:53 pm (PST).

Two aftershocks followed the quake, a 3.6 magnitude and a 3.3 magnitude at  4:56 pm.

The earthquake was slightly felt in Los Angeles, CA. There are no reports of damages or injuries.

More details here: http://earthquake.usgs.gov/earthquakes/recenteqsus/Quakes/ci10736069.html