Quakes

If you are a Boggy Thicket regular, you know that I have been predicting for months that a major quake is due in California.  So far, California isn’t cooperating, but we are hearing more and more news of tremors in unlikely places – a couple in Oklahoma, and two in the past week in Texas:

LUBBOCK, Texas (AP) - Texas has had its second minor earthquake this week.

The U.S. Geological Survey website shows that the 3.4 magnitude quake happened at 12:47 p.m. Friday and was centered 15 miles north of Snyder in West Texas. The area is 68 miles southeast of Lubbock.

The Scurry County sheriff's office said there were no immediate reports of injury or damage.

On Wednesday the USGS reported a 2.7 magnitude earthquake about 29 miles southwest of Dallas.

It was the second quake in the Snyder area in less than a month. On Nov. 24, a 3.0 magnitude quake was centered 17 miles north-northeast of Snyder.

A rare South Texas earthquake with a 4.8 magnitude was recorded Oct. 20 about 37 miles northwest of Beeville.

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Meanwhile, I came across this class exercise from the University of California:

Prediction or Prevention?

©1995 The Regents of the University of California

To do this activity...
The main lesson outline will help you understand the questions in this activity. However, you do not need to have done the other activities.

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Congratulations! You have just joined a team of geologists assigned to predict or prevent earthquakes. This is a challenging job! Read through the following two descriptions to determine which team you are joining. Prepare to write answers to the issues for each team and to discuss your answers with classmates. (Your instructor may assign you one or both teams.)

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Prediction Team:

You are on a geologic team with the task of predicting earthquakes. Your team has a new prediction method that has never been tested before, but you believe it will predict some earthquakes larger than magnitude 5.0 on the Richter scale.

One day at work, your instruments tell you that there is a 3% chance of a 7.2-magnitude earthquake in San Fransisco within the next 15 minutes. What should you do? Answer these questions:

a) What emergency preparations would you recommend to the people and businesses of San Francisco in the next 15 minutes?

b) If you send an emergency warning, will it save lives? How many might be saved?

c) If the mass population panics, could the panic itself cause deaths even without a quake? Would it cause major economic problems (e.g. loss of business, congestion of freeways, overloading of telephone lines, etc.)?

d) Which situation would be worse: (1) You send a warning to San Francisco but the quake does not occur; or (2) you do NOT send a warning and the quake does occur? Explain your reasons.

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Prevention Team:

Your team has been developing a method to prevent large earthquakes from occurring. After much research your team has made five important conclusions:

1. An earthquake fault in your local area has built up enough strain to cause a major earthquake of magnitude 6.0 or larger.

2. There is a 50% chance that this major earthquake will strike within the next 10 years.

3 You may be able to prevent this single large quake by causing a series of about 25 small quakes in the same location to release the strain in the rocks.

4. You predict that each of these small quakes will be less than 5 on the Richter scale.

5. There is a 10% chance that the series of small quakes would actually trigger the major quake instead of preventing it.

Now here are the questions you must answer:

a) How much damage would be caused by 25 quakes measuring 5.0? Is this better or worse than one quake measuring 6.0? Who would benefit more from the 25 smaller quakes? Who would be more seriously affected by 25 small quakes?

b) Considering the risk of setting off the major quake, should you attempt the 25 smaller quakes? Why or why not? If a major quake does occur, can you be held responsible? If you do not attempt to prevent the larger quake and it actually does occur, can you be held responsible, since you had a method to prevent it?