The release of accumulated stress at a particular point during an

The release of accumulated stress at a particular point during an earthquake alters the shear and normal stresses along the tectonic plate boundary and surrounding fault lines. According to geophysical theory, the Coulomb Failure Stress Change, which is the estimated alteration and resultant transfer of shear and normal stresses along a plate margin, is a function of change in shear stress along a fault and secondarily the change in normal stress along a fault and the change in pore pressure in the fault zone, the latter two factors scaling according to the friction coefficient characteristic to the plate margin.

By measuring and calculating the stress transfer following seismic activity, it is possible to subsequently construct basic contour maps of regions where there have been positive stress changes and are therefore of higher risk of being potential epicenters of future large earthquakes. Calculations have revealed that when an earthquake occurs, approximately 80% of the energy is released as seismic waves, whereas the remaining 20% is stored and transferred to different locations along the fault, making those specific regions more susceptible to future earthquakes.

Predicting earthquakes by using the theory of stress transfer has important potential applications. The main rival technique for forecasting, the statistical analysis of patterns in seismic activity, suffers from a contradiction. Foreshocks are deemed evidence of the potential for a future high-magnitude earthquake, but the lack of foreshocks along faults known to be active has been considered an equally plausible potential precursor for large events.

The stress transfer theory has been used to predict the location of a magnitude 7.4 earthquake that occurred two years later in the port city of Izmit, Turkey, killing more than 30,000 people. A limitation of the theory as currently applied, due to insufficient understanding of plate kinematics, is that refining predictions with temporal constraints appears to be far more problematic; the team that gave the Izmit prediction had forecast an event near the city within thirty years.

1. The author is primarily concerned with

A. advocating a return to an older scientific technique
B. explaining an application of geophysical theory
C. detailing differences between two opposing scientific techniques
D. describing the events leading to a geophysical prediction
E. challenging the logical underpinnings of a practical theory

2. According to the passage, the primary method of predicting earthquakes other than by applying the theory of stress transfer is based on

A. patterns of prior seismic activity
B. measurements of stress transferred and stored in a fault
C. contour maps of regions of interest
D. probabilistic simulations
E. the change of pressure in a fault zone

3. The passage indicates that which of the following steps is involved in predicting the location of a future earthquake according to the stress transfer theory?

A. Focusing on areas where prior seismic activity has not been observed
B. Focusing on the regions of tectonic plates farthest from their boundaries
C. Using measurements from previous seismic events to identify locations of stress
D. Using statistical analysis of which prior predictions were correct and incorrect
E. Constructing basic contour maps of the landscape features along fault lines

4. Which of the following statements about predictions of earthquakes is supported by the information in the passage?

A. The number of earthquakes predicted successfully on a regular basis has increased since the development of the stress transfer theory.
B. The existence or nonexistence of prior seismic activity in a location is not a definitive indicator of future activity in that location.
C. It is unlikely that refining the temporal aspect of predictions made by the stress transfer theory will be improved in the near future.
D. Modern scientists are divided on which of the two prediction methods discussed in the passage is currently more useful.
E. More successful predictions based on the theory of stress transfer are required before the prediction method using stress transfer can be considered valid.

5. In can be inferred from the passage that which of the following is most difficult to determine?

A. The change in pore pressure in a fault zone caused by an earthquake
B. The stress changes along a tectonic plate boundary caused by an earthquake
C. The probable epicenter of a future seismic event along a fault line
D. The timing of a future seismic event corresponding to a particular probable epicenter
E. The friction coefficient characteristic to the plate margin

6. The theory described in the highlighted text relates to the prediction techniques discussed in the passage in which of the following ways?

A. It provides a theoretical basis of tectonic activity that is applied in one of the prediction methods discussed.
B. It suggests that since foreshocks are evidence of future seismic activity, but not definitive evidence, the two prediction methods should be used jointly.
C. It suggests that there may not be enough certainty inherent to plate kinematics to enable the development of a reliable prediction method.
D. It corrects existing theories about the transfer of tectonic stress, and thus provides a basis for correcting current prediction methods.
E. It suggests that simple prediction methods have a higher success rate in the than do more recently developed methods.

7. According to the passage, methods of predicting earthquakes that are widely used today are based on which of the following facts?

A. Future earthquakes will be larger in magnitude than past earthquakes.
B. Earthquakes are inherently unpredictable.
C. Earthquakes tend to occur along fault lines.
D. Some types of earthquakes are easier to predict than others.
E. Some future locations of major earthquakes have been identified, although the exact timing of those future earthquakes is not known.