Causing Smaller Earthquakes to Prevent Big Ones?

November 18, 2008

I just got back from Los Angeles, where last week millions of people participated in a gigantic emergency preparedness drill. An Associated Press article reports:

People across Southern California on Thursday looked like they had stepped out of a disaster movie. Children ducked under their desks. Victims with fake blood lay on the ground. First responders sprang into action to treat the "wounded."

The controlled chaos was all part of a mock "Big One" — an earthquake drill billed as the largest in U.S. history and aimed at testing the preparedness of governments, emergency responders and residents.

At 10 a.m., a cast of millions dropped to the ground, covered their heads and held onto furniture. Local television stations interrupted their regular programming to announce the drill and covered it as they would a major earthquake, though with continual reminders that the emergency wasn't real.

The reason for all this is that the L.A. megalopolis sprawls across a network of earthquake faults that makes it highly vulnerable to seismic catastrophes. According to Science Daily, scientists calculate that the probability of a 6.7-magnitude quake striking the Los Angeles area over the next 30 years is 67 percent. (If you’re unclear about what the numbers on the Richter scale mean, here’s an article from our companion site, HowStuffWorks.com, on the subject.) But things could get even worse than that. Scientists say Southern California is overdue for a quake along its portion of the San Andreas Fault. Such a quake could well approximate the one that occurred farther to the north, back in 1857. The 7.9 Fort Tejon earthquake  was so powerful that it reversed the flow of the Kern River and tossed fish from a lake onto the shore. Scientists estimate that a quake that size in the L.A. region today might kill 1,800 people and cause upwards of $200 billion in property damage. And that’s probably being conservative.

So preparedness is important. But wouldn’t it be better if we could somehow prevent big earthquakes from occurring?

An Israeli outfit called TerraMoto believes that it may have the answer. From the company’s Web site, here’s a description:

TerraMoto has developed a new patented technology which precisely charts the subterranean pressure distribution along the fault lines. This technology allows to predict the magnitude of an earthquake and its risk level. Preventing the earthquake can be established by controllably and gradually releasing pressures by a series of small explosions at the high pressure points.

A story from the Israeli news Web site IsraCast.com provides more details. TerraMoto would build a series of measuring stations along an earthquake fault and equip them with special devices called geophones to detect the faint quakes that occur continuously along the fault. Using triangulation, the scientists would then identify the danger spot along the fault where energy is being accumulated. They then would employ ultrasound surveys and mathematical modeling to determine how much pressure the spot can endure and how much energy it might release upon shattering. Finally, they would drill up to 10 kilometers into the ground and place explosives inside the rock, and then detonate a series of controlled blasts. Essentially, they would trigger a number of small, manmade quakes, which would gradually relieve the pent-up energy and prevent a gigantic one.

It sounds good, but as usual, there are a few catches. Popular Science blogger Jim Oberg writes:

But even if such a proposal could get past the inevitable legal and environmental hurdles, geologists warn that replacing one big earthquake with a swarm of smaller ones might actually be riskier.

William Ellsworth, chief scientist of the U.S. Geological Survey's earthquake hazard team, points out that because earthquake energy multiplies with each point on the Richter scale, it would take roughly 1,000 magnitude — 6 quakes to dissipate the energy of a single magnitude — 8 quake. Another problem is that many fault lines are not discovered until an earthquake occurs.

Proponents of earthquake engineering argue that induced quakes would be safer than unplanned ones, because local residents and emergency services would have time to prepare for them. But most geologists aren't convinced. Thomas J. Ahrens, a geophysics professor at the California Institute of Technology, cautions that mini quakes “may easily get out of control.”

So, what do you think? Should we try setting off small man-made quakes to stave off the Big One, or should Angelenos concentrate on stocking up on batteries and bottled water instead? Express your opinion below.

Comments

[Mothra]

I think this idea is way too dangerous to try.

[Caffeine Driven Stress Magnet]

I agree. This one really scares me. What if the theory is wrong and they actually triggered a big earthquake?

[Monkey Man]

This is just what we don't need.

[Dr. Farnsworth]

How much damage would these "small" preemptive earthquakes cause? I don't see anything about that.

[Horatio]

1. What magnitude would these "small" preemptive earthquakes have to be?

2. How much risk is there that the planned explosions might inadvertently cause a big quake?

3. How much would all of this cost, and who would foot the bill?

4. Who would give scientists permission to do this? Would a local government decide, or would the federal government make the call? The decision to set off smaller quakes is sure to arouse controversy, especially if they cause damage.

[Astroboy!]

I WANT TO SET OFF SOME EARTHQUAKES!!!!!!!!!!!

[MACARIO]

RE-ENTER THE EARTHS ATMOSPHERE OVER CALIFORNIA.
I REMEMBER A TIDAL WAVE HIT AROUND THE TIME A SHUTTLE RETURN
OVER THE AUSTRAILA PART OF THE WORLD BY INDO.