
Popular Science
August 19, 2015 [Just found this in social media.]
Mary Beth Griggs

How California is predicting and preparing for the inevitable. No image credit.
There’s a crack in California. It stretches for 800 miles, from the Salton Sea in the south, to Cape Mendocino in the north. It runs through vineyards and subway stations, power lines and water mains. Millions live and work alongside the crack, many passing over it (966 roads cross the line) every day. For most, it warrants hardly a thought. Yet in an instant, that crack, the San Andreas fault line, could ruin lives and cripple the national economy.
In one scenario produced by the United States Geological Survey, researchers found that a big quake along the San Andreas could kill 1,800 people, injure 55,000 and wreak $200 million in damage. It could take years, nearly a decade, for California to recover.
On the bright side, during the process of building and maintaining all that infrastructure that crosses the fault, geologists have gotten an up-close and personal look at it over the past several decades, contributing to a growing and extensive body of work. While the future remains uncertain (no one can predict when an earthquake will strike) people living near the fault are better prepared than they have ever been before.
The Trouble With Faults
All of the land on Earth, including the ocean floors, is divided into relatively thin, brittle segments of rock that float on top of a much thicker layer of softer rock called the mantle. The largest of these segments are called tectonic plates, and roughly correspond with the continents and subcontinents of the earth.
The San Andreas fault is a boundary between two of these tectonic plates. In California, along the fault, the two plates–the Pacific plate and the North American plate–are rubbing past each other, like you might slip by someone in a crowded room. The Pacific plate is moving generally northwest, headed towards Alaska and Japan, while the North American plate heads southwest.
In a simplified, ideal world, this movement would happen easily and smoothly. Because it covers such a large area, not all of the fault moves at the same time. In the middle, things are moving rather smoothly, with part of the Pacific plate gliding by the North American plate with relative ease, a segment that scientists say is ‘creeping’.
It’s at the northern and southern extremes where things get tricky. The real problems begin when the plates get stuck, or wedged together.
Visions Of A Disaster
The fear of a huge earthquake from the San Andreas devastating the west coast has been rich fodder for disaster films, including Superman and, more recently, San Andreas. The good news is that the worst-case scenarios in those films are completely impossible. California will not sink into the sea, and even the largest possible earthquake is short of anything that the Rock had to wrestle with.
But disasters have happened.
In 1906, the northern segment of the fault, near the city of San Francisco, ruptured along nearly 300 miles, causing a huge earthquake that led to fires, downed buildings, and thousands of casualties. The death toll was between 700 and 2,800.
Meanwhile, other segments of the fault, like one south of Los Angeles that hasn’t seen a large earthquake since 1690, are considered stalled. Centuries of energy are built up and ready to be released. When? Nobody knows.
Recent analyses suggest that in a worst-case scenario, the San Andreas would beget an earthquake ranking an 8.3 on the Richter scale, a logarithmic scale on which a 6.0 is ten times as powerful as a 5.0, a 7.0 ten times as powerful as a 6.0, and so forth. To put that in context, earthquakes under 2.5 are rarely felt. Earthquakes under 6.0 can cause some damage to buildings, but aren’t major events. Above that level things start to get interesting. The largest recorded quake in the United States was a 9.2 earthquake that hit Alaska in 1964.
“That would require the San Andreas to rupture wall to wall from its southern extremis to up to Cape Mendocino,” says Tom Jordan, the director of the Southern California Earthquake Center at The University of Southern California,. He explains that the creeping segment in the middle acts as a buffer, making the 8.3-magnitude earthquake much less plausible than some other options.
Even if the 8.3 earthquake never materializes, scientists worry that a rupture along the long-inactive southern segment could be devastating, compounded by the large population in the area. The 1989 Loma Prieta earthquake that shook San Francisco was only a 6.9, but it caused billions of dollars in damage injured over 3,000 people, and killed 63.
“The San Andreas lies close to the coastline where people live,” Jordan says. The valleys along the coast that proved so enticing to the settlers who founded cities like Los Angeles are large areas of sedimentary rock that could be hugely problematic in an earthquake.
“Even though L.A. is 30 miles from the San Andreas, it can still get very strong ground motion,” Jordan says. “The sediments shake like bowls of jelly.”
But even just a medium-bad scenario could be enough to kill hundreds and ruin the economy.
Researchers like Jordan are building up huge, incredibly detailed 3D maps of the geology near the San Andreas fault. These maps can be used to generate detailed assessments for almost any possible earthquake scenario that might happen along the fault.
In 2008, United States Geological Survey scientist Lucy Jones and colleagues published the ShakeOut scenario, a detailed report that looked at what could happen if a large (magnitude 7.8) earthquake occurred along the southern leg of the fault.

Simulated magnitude-8.0 earthquake.
Just like the 1906 earthquake in San Francisco, people living in the area would be without power and water for interminable lengths of time, and in the immediate aftermath, firefighters would not have access to water to fight the fires that would spring up in the wake of the disaster. And in California’s current drought, the fires after the earthquake could prove more devastating than the shaking itself.
Dodging A Bullet
Scientists may not be able to predict where and when a strike will hit, but the more they understand what could happen, the more they can help plan for any event. Last winter, Los Angeles Mayor Eric Garcetti announced a plan called Resilience By Design, that tries to address the huge risk facing the city if there was an earthquake along the San Andreas.
“It is highly unlikely we’ll make a century [without a large earthquake]” said Jones, who also headed up the Resilience by Design group. Reinforcing the city’s lifelines, like roads and utilities, is a huge priority.
Fortunately, California has a precedent to the north.
In 2002, the Denali fault in Alaska slipped and caused an earthquake with a magnitude of 7.9, the largest inland earthquake recorded in the country in 150 years. And running right across that fault was the Trans-Alaska Pipeline, an 800-mile long piece of infrastructure that carries 550,000 barrels of crude across near-pristine tundra every day.
“It was the biggest ecological disaster that never happened.” Jones said.
The pipeline was built to accommodate the movement of the earth, so that even though the earth slid by up to 18 feet in the 2002 earthquake, the pipeline didn’t break, averting a serious oil spill. To avoid rupturing, the engineers designed the above-ground portion of the pipeline in an intentional zig-zag pattern instead of a straight line, giving the pipeline flexibility. The pipeline itself can also slide. Instead of being anchored in the permafrost, part of the pipeline sit on Teflon-coated ‘shoes’ which rest on huge steel beams that sit perpendicular to the pipeline. In the event of shaking, segments of the pipe can slide on the beams like train cars on rails, without breaking.

Denali Pipeline. The zig-zag pattern allows it to flex and move without breaking.
The Next Quake
In California, water pipes and electrical lines could be built or retrofitted with similar flexibility. Researchers are even working on building earthquake-resistant houses that can slide back and forth on instead of crumbling. Unlike traditional homes, which sit on a foundation, these earthquake-resistant homes sit on sliders made out of steel, that, just like the Trans-Alaska Pipeline, can slide over the shaking ground instead of breaking.
The internet of everything has a role to play here too. In the future, networks of devices scattered across the southern California landscape could monitor an earthquake as it starts. This seismic network could send out an alert as the earthquake propagates through the earth, giving utilities precious seconds of warning to shut off valves in pipes along the fault, shut off power to prevent damage, and even send an alert to operating rooms, allowing a surgeon to remove her scalpel from a patient before the shaking even begins.
Scientists already have a seismic network in California, but more seismic sensors and technical development are needed to get the fledgling network to the next level. Unfortunately, those developments require money, and getting enough funding to build the next system has been elusive.
The cost for a truly robust alert system is estimated at $80 million for California alone, and $120 million for the whole West Coast. But funding is sparse. Earlier this year, President Obama pledged $5 million. The first sensors are already being used by San Francisco’s mass transit system to slow down trains in the event of an earthquake.
To see what the future of California might look like, one only has to glance west towards Japan, where even their fastest trains come to a halt at the first sign of an earthquake, elevators allow people to disembark, and people get warnings on radio, TV, and cell phones.
Similar techniques could be employed near Los Angeles, Jones says, making the city ready to bounce back from even the worst earthquake that the San Andreas can throw at the city.
Ralph Waldo Emerson once said that “we learn geology the morning after the earthquake.” Fortunately for Los Angeles, plenty of people, from geologists to city and emergency planners, have no intention of waiting that long.
California Earthquakes Since 1900
Earthquakes in California cluster along its fault lines. Here are the epicenters of the state’s strongest 20th-century quakes. Even though truly massive quakes on the San Andreas are rare, it’s still a very active line, with many dots appearing along its length.
Earthquakes in California cluster along its fault lines. Here are the epicenters of the state’s strongest 20th-century quakes. Even though truly massive quakes on the San Andreas are rare, it’s still a very active line, with many dots appearing along its length.
The animation includes all California earthquakes between January 1900 and July 2015 with magnitude 4.2 or greater. The circle size represents earthquake magnitude while color represents date, with the earliest quakes in yellow and the most recent in red. The San Andreas appears as a red line running down the left side of the state. Better seismic sensors detect weaker earthquakes, so milder quakes don’t appear in the early years of the animation.

Meet The Quake-Catcher Network

Quake-Catcher Network
The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.
After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).
The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).
The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).
There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.
Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.
USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.
If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.
BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.
Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.
Below, the QCN Quake Catcher Network map

ShakeAlert: An Earthquake Early Warning System for the West Coast of the United States

The U. S. Geological Survey (USGS) along with a coalition of State and university partners is developing and testing an earthquake early warning (EEW) system called ShakeAlert for the west coast of the United States. Long term funding must be secured before the system can begin sending general public notifications, however, some limited pilot projects are active and more are being developed. The USGS has set the goal of beginning limited public notifications in 2018.
Watch a video describing how ShakeAlert works in English or Spanish.
The primary project partners include:
United States Geological Survey
California Governor’s Office of Emergency Services (CalOES)
California Geological Survey
California Institute of Technology
University of California Berkeley
University of Washington
University of Oregon
Gordon and Betty Moore Foundation
The Earthquake Threat
Earthquakes pose a national challenge because more than 143 million Americans live in areas of significant seismic risk across 39 states. Most of our Nation’s earthquake risk is concentrated on the West Coast of the United States. The Federal Emergency Management Agency (FEMA) has estimated the average annualized loss from earthquakes, nationwide, to be $5.3 billion, with 77 percent of that figure ($4.1 billion) coming from California, Washington, and Oregon, and 66 percent ($3.5 billion) from California alone. In the next 30 years, California has a 99.7 percent chance of a magnitude 6.7 or larger earthquake and the Pacific Northwest has a 10 percent chance of a magnitude 8 to 9 megathrust earthquake on the Cascadia subduction zone.
Part of the Solution
Today, the technology exists to detect earthquakes, so quickly, that an alert can reach some areas before strong shaking arrives. The purpose of the ShakeAlert system is to identify and characterize an earthquake a few seconds after it begins, calculate the likely intensity of ground shaking that will result, and deliver warnings to people and infrastructure in harm’s way. This can be done by detecting the first energy to radiate from an earthquake, the P-wave energy, which rarely causes damage. Using P-wave information, we first estimate the location and the magnitude of the earthquake. Then, the anticipated ground shaking across the region to be affected is estimated and a warning is provided to local populations. The method can provide warning before the S-wave arrives, bringing the strong shaking that usually causes most of the damage.
Studies of earthquake early warning methods in California have shown that the warning time would range from a few seconds to a few tens of seconds. ShakeAlert can give enough time to slow trains and taxiing planes, to prevent cars from entering bridges and tunnels, to move away from dangerous machines or chemicals in work environments and to take cover under a desk, or to automatically shut down and isolate industrial systems. Taking such actions before shaking starts can reduce damage and casualties during an earthquake. It can also prevent cascading failures in the aftermath of an event. For example, isolating utilities before shaking starts can reduce the number of fire initiations.
System Goal
The USGS will issue public warnings of potentially damaging earthquakes and provide warning parameter data to government agencies and private users on a region-by-region basis, as soon as the ShakeAlert system, its products, and its parametric data meet minimum quality and reliability standards in those geographic regions. The USGS has set the goal of beginning limited public notifications in 2018. Product availability will expand geographically via ANSS regional seismic networks, such that ShakeAlert products and warnings become available for all regions with dense seismic instrumentation.
Current Status
The West Coast ShakeAlert system is being developed by expanding and upgrading the infrastructure of regional seismic networks that are part of the Advanced National Seismic System (ANSS); the California Integrated Seismic Network (CISN) is made up of the Southern California Seismic Network, SCSN) and the Northern California Seismic System, NCSS and the Pacific Northwest Seismic Network (PNSN). This enables the USGS and ANSS to leverage their substantial investment in sensor networks, data telemetry systems, data processing centers, and software for earthquake monitoring activities residing in these network centers. The ShakeAlert system has been sending live alerts to “beta” users in California since January of 2012 and in the Pacific Northwest since February of 2015.
In February of 2016 the USGS, along with its partners, rolled-out the next-generation ShakeAlert early warning test system in California joined by Oregon and Washington in April 2017. This West Coast-wide “production prototype” has been designed for redundant, reliable operations. The system includes geographically distributed servers, and allows for automatic fail-over if connection is lost.
This next-generation system will not yet support public warnings but does allow selected early adopters to develop and deploy pilot implementations that take protective actions triggered by the ShakeAlert notifications in areas with sufficient sensor coverage.
Authorities
The USGS will develop and operate the ShakeAlert system, and issue public notifications under collaborative authorities with FEMA, as part of the National Earthquake Hazard Reduction Program, as enacted by the Earthquake Hazards Reduction Act of 1977, 42 U.S.C. §§ 7704 SEC. 2.
For More Information
Robert de Groot, ShakeAlert National Coordinator for Communication, Education, and Outreach
rdegroot@usgs.gov
626-583-7225
Learn more about EEW Research
ShakeAlert Fact Sheet
ShakeAlert Implementation Plan
See the full article here .
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