Earthquake Prediction Tools

[Mark Sedenquist]

For those contemplating road trips in the California area -- there is a new prediction tool that you can view that provides probabilities of major earthquakes in the region. It is updated hourly and purports to show "real time" data and joins online tools like those used to predict the incidence of "Big Weather" and tornadoes. It is an amazing tool. But somehow the notion of trying to be in the spot of a major earthquake seem a bit crazy to me. What do you think?

Mark

[PNW Judy]

Having ridden through a few of these big hiccups myself up here in the PNW, and once while visiting Disneyland, I'd only use that to tell me where to avoid. So far, the worst damage I've experienced is some pictures falling from the walls, some cracked plaster, and our chimney partially falling down. No injuries. I don't wanna tempt fate though.

[Mark Sedenquist]

Having ridden through a few of these big hiccups myself up here in the PNW,

If you find yourself already in place when an EQ is happening, it can be sort of fun -- to a point. I have probably experienced 100 or so that I can remember during my 30+ year sojourn in Southern California. It turns out that Nevada (home to the proposed nuclear waste facility) also experiences earthquakes on a regular basis -- but they tend to be in the 2.1 to 3.1 size -- not all that compelling. As a Red Cross disaster specialist I have been in the middle of the aftermath of large earthquakes and it can be disconcerting to be crawling under damaged buildings when the ground is still shaking. For roadtrippers it can be a truly amazing sight to see the seismic ground waves rolling the freeway surface in front of you. If it happens to you and you see a ground effect rolling down the freeway towards you -- grasp the steering wheel very lighty just before the wave gets to you and imagine your car is a surfboard in the ocean -- it will ride up and over the wave -- just remember to be ready to take evasive action on the other side if your neighboring drivers are somewhat freaked! This happens in a millisecond -- but I can still remember the thrill of my last time.

One other thing -- if you are in a building and the ground starts to rumble -- don't act cool -- move under a sturdy table or if one is not available get to a door jamb (frame around the doorway). But do not stand in the door way -- it always amazes me that no one seems to teach anyone what you are supposed to do in the door frame. So -- quick lesson -- sit down on the floor -- position your butt hard against the bottom of the door frame on the opposite side from the door brace your legs to keep the door from swinging back on you (closing) -- duck your head and cover the back of your neck with your hands. If the earthquake is severe the door frame will provide some structural support and reduce the chance that things will be falling on your head. I have seen grown adults (who must have known better) move to a door opening in a 'quake -- casually stand in the opening and then get knocked down (and out) when the force of the 'quake moved the door frame suficiently to hit them in the face.

Again from a roadtripper's perspective -- even in major earthquakes it is often hard to feel the ground shaking while inside a moving vehicle. Best clues -- the stop signs are swinging and there is no wind... a straight line of dust poofs on the hillsides -- people swarming out of perfectly good and safe buildings directly in the potential path of stuff falling on them (another don't do this).

Earthquakes are not as likely as tornadoes -- but they are still a part of the western states roadtripping experience. Might as well enjoy them -- to the extent that is possible. For a scary true-life-as-it-might-happen-one-day book read Marc Reisner's A Dangerous Place: California's Unsettling Fate.

And remember -- every roadtrip is supposed to be an adventure!

Mark

[AZBuck]

I am actually a bit surprised that an outfit as reputable as the USGS has put something like this out there. Although they clearly say that "The primary use of this map is educational.", I'm afraid that such caveats will fall on the same blind eyes and deaf ears as all those "Professional driver on closed course" disclaimers on car ads showing a Joe Blow look-alike pushing the latest Detroit iron through the air over, and doing doughnuts on, what look for all the world like public roads.

There are several problems here. We are nowhere near being able to predict earthquakes with anything even approaching precision in time and place. This map glosses over this by giving probabilities that a quake of a certain strength will happen within a certain time frame - note that those probabilities are all low. Secondly it only 'predicts' very mild quakes which occur with enough frequency that we have useable statistics for them, and then glosses over this by using the Modified Mercalli Intensity scale, on which a level VI quake is defined by "Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight (Emphasis added)." However, most people are used to the Richter Scale for earthquakes on which a magnitude 6 quake usually kills people. This discrepancy only gets worse with increasing numbers, because on the Richter scale, each time the scale value increases by 1, the quake energy increases by a factor of 10!

But, to be fair, I guess the real test is - is it predictive?. Last night there was a magnitude 7 quake in northern California - just offshore near the Oregon state line - in an area where this map predicts nearly its LOWEST probability of a quake occurring, 1 in several hundred thousand. There are, indeed, known places where there is increased risk for an earthquake, areas along faults that have not had a quake for prolonged periods of time, but where there have been quakes to either side, so called 'locked' sections of a fault. But when they will let go and how big the fault will be when they do are at best educated guess work. I wouldn't alter my plans based on this map.

AZBuck

[Mark Sedenquist]

I am actually a bit surprised that an outfit as reputable as the USGS has put something like this out there.

I don't think anyone is going to view this page with the same kind of acceptance as we view weather maps -- (although even weather prediction is more voodoo than science) but it is an interesting waypoint on the path to true predictability. I agree with your comments and thank you for the analysis.

Mark

[AZBuck]

..Sorry, got my "peer review" hat on there for a bit. But you never know how people will react to government predictions.

AZBuck

[Mark Sedenquist]

..Sorry, got my "peer review" hat on there for a bit. But you never know how people will react to government predictions.AZBuck

I see examples of passion every day on this forum. Passion tempered by real-life expertise is what sets this Forum apart from the rest of the Web. So, no problem -- knowledge is always a good thing.

[PNW Judy]

If you find yourself already in place when an EQ is happening, it can be sort of fun -- to a point.

Actually, every earthquake I've been in has been fun. Well, the one that ruined our chimney wasn't fun AFTER I discovered that particular damage. But it was great fun during it.

I'm not scared of earthquakes but that's also because I've never been in one bad enough where people have been injured or where quite serious damage has occurred. Well, at least not in my general area anyway. Maybe closer to the epicenter that might be a different matter.

One earthquake happened while I was in a big, chair-and-a-half recliner, leaned back with my feet up half asleep. It was a rolling type of quake so it felt like I was on a roller coaster. It lasted quite awhile, probably at least 30-40 seconds, maybe a tad more? It was actually fun at first until I realized that banging on the wall directly above my head was a very heavy painting in a heavy wooden antique frame. I would guess it weighs about 10#. I wasn't too thrilled with the idea of this landing on my head. So I tried to get out of the recliner. No way. I just could not get the momentum going to sit up much less crawl out of the big lap of this recliner. That was my only spooky moment. I'm quite glad that painting didn't fall on my head after all.

[AZBuck]

They did correctly predict today's quake. It was smack dab in the center of their highest probability zone!

Credit where credit is due.

AZBuck

[Mark Sedenquist]

They did correctly predict today's quake. It was smack dab in the center of their highest probability zone!

That is pretty funny -- was it the one near Yucaipa or some other place?

Mark