Environmental Geology lecture outline - Earthquake engineering.

"A bad earthquake at once destroys our oldest associations: the earth, the very emblem of solidity, has moved beneath our feet like a thin crust over a fluid: one second of time has created in the mind a strange idea of insecurity, which hours of reflection would not have produced. .... it is a bitter and humiliating things to see works, which have cost man so much time and labour, overthrown in one moment. " Darwin 1845, on his experience of an earthquake in Concepcion, South America

Given difficulty or even inability to predict earthquakes an alternate approach is simply to learn to live with them. Most critical in such approach is to build structures so that they can survive an earthquake.

Example of design criteria (the goal):

Substrate concerns:

Earthquake forces:

Importance of building material and flexibility, and the concept of cyclic loading.

Importance of building shape:

Approaches in increasing safety of building:

Types of building failure typical during an earthquake:

What to do for domestic abodes?

For large pipelines -> shutoff valves connected to accelerometers, flexible sections were cross fault.

Cost? 5% of original without, 50-100% as retrofit.

Critical facilities?

Legal codification of earthquake engineering?

In class seismic hazard assessment exercise:

Split up, self-organize into groups of 4 to 5 people to complete the exercise. Each group willbe given a section of Omaha to cover

The scenario is a Richter magnitude 6.8 has occurred just S of Omaha. Remember that such an occurrence is unlikely, although not impossible.

Consider the assigned area and think of the following questions for 5-10 minutes or so:

Write out a list of conclusions on the sheet provided, and pick a spokesperson to present them.

Try to be realistic, and not over dramatize. The idea is to scientifically evaluate to the best of your ability.

Areas to consider:

H.D. Maher Jr., 3/9/98

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