Quiz questions

• 3 Feb - Sketch the offset in geological strata produced by 'normal' and 'reverse' faults. Show with arrows the stress regimes that can produce these types of faults.

   

• 5 Feb - What are some aspects of building location and earthquake ground motion that affect the damage inflicted on buildings during an earthquake?

8 Feb - What are the earthquake hazards in "locked" versus "creeping" segments of a fault?

Answer:

In a creeping segment of a fault there are many smaller earthquakes that release much of the energy. The largest earthquakes on creeping segments of the San Andreas fault are rarely bigger than magnitude 6.

In a locked segment of a fault there are few smaller earthquakes. All the available energy is stored for release in rare, very large, earthquakes. These quakes can be of magnitude 8 or greater on locked parts of the San Andreas Fault.

10 Feb - What is the elastic rebound theory of faulting?

Answer:

In the elastic rebound theory, energy is stored elastically in rocks as they deform due to the motions of the crustal blocks. When the stress builds up to the level needed to break the rock or make the fault slip, an earthquake occurs. The earthquake releases most or all the stress in the rock. This is like the stretching and breaking of a rubber band.

12 Feb - Where in the central United States are there likely to be earthquakes? What kind of damage have previous quakes in this areaq caused?

Answer:

The most likley area for large damaging quakes in the central US is in the New Madrid area. This is in the southeastern part of Missouri. Previous large earthquakes ther in the early 1800's changed the course of the Mississippi, and caused major liquifaction of river sands and causing the buildings of New Madrid to sink into the mud.