Presentation on theme: "Earthquake Prediction Methods. Earthquake predictions Because earthquakes do not happen on regular intervals it is difficult to predict when the next."— Presentation transcript:
Earthquake predictions Because earthquakes do not happen on regular intervals it is difficult to predict when the next one will occur. Methods for predicting earthquakes on these faults vary; none of them being 100% accurate. Predictions are given for a time frame instead of an exact date.
Why is it important? http://www.teachersdomain.org/resource/ ess05.sci.ess.earthsys.japan/ http://www.teachersdomain.org/resource/ ess05.sci.ess.earthsys.japan/ http://www.teachersdomain.org/resource/ ess05.sci.ess.earthsys.japan/ Early prediction theories were based on patterns, and timing between earthquakes
Statistical Methods Must collect data on location and magnitude of earthquakes okay for smaller earthquakes but not for larger earthquakes. This data is used in several statistical predictions
Statistical Methods Recurrence Frequency Looks for relationship between the magnitude and repetition of earthquakes. Assumes that the same set of conditions leading to an earthquake occur each time. Dependent on large amounts of historical data.
Statistical Methods Seismic Gap Theory A seismic gap is an area along a fault where there has not been any earthquake activity for a long period of time. Focuses on patterns in seismicity.. If a change in the pattern occurs, there is a chance for an earthquake.
Physical measurements Events that occur before an earthquake can include: Increase in the rate of seismic creep Gradual tilting of the land near the fault zone Drop or rise in the water level of a well Decrease in the number of foreshocks Dramatic changes in animal behavior
Physical measurements Fault Creep Measurements Measures the slow rate of movement at the fault. Lots of fault creep means a small chance of a big earthquake. Low amounts of fault creep means a high chance of a big earthquake.
Physical measurements Drop or rise in the water level of a well Large surface waves force particles of rock near to the surface which changes water levels in a well. Water levels can be affected by any fault creeps, crust tilts, or other seismic activity. We can drill wells in certain locations to measure dramatic changes in water levels.
Physical and Geophysical measurements and observations Animal behavior unusual animal behavior can be a way to predict earthquakes The Chinese started recording unusual animal behavior and successfully predicted an earthquake in 1975 3 months before it struck.
Physical and Geophysical measurements and observations Unusual animal behavior includes: Hibernating animals leaving their underground nests Animals refusing to go into pens Animals seeking higher ground Birds vacating the area Deep water fish come closer to the surface
Physical measurements This type of prediction requires a lot of data collection and review to find patterns. Problem with this method is that some of characteristics are geographically specific so they cannot be applied to different areas.
Conclusion Predicting earthquakes is not yet possible The more data we review and the more patterns we find the better the predictions