Fault Lines The Awesome Power of Earth's Tectonic Plates
The Race is on to Predict Dangerous Earthquakes
by Cecilia Gonzales, age 15
The Earth’s crust is made up of tectonic plates that continuously shift. Between those plates are fault lines, or fractures, that are created when adjoining plates move against to each other.
One example of a fault line is the Eriquillo-Plantain Garden Fault that runs east to west across the Caribbean. Slippage from this fault line resulted in the enormous earthquake that devastated the country of Haiti last year.
California’s San Andreas Fault is one of the most well known faults in the world. It is created by a strike-slip system, meaning the break is caused by a side-by-side plate tectonic motion. Too much tectonic motion causes a build up of stress in the faults.
In order to study these deep stresses, scientists have installed the San Andreas Fault Observatory at Depth. The observatory is made up of a borehole drilled two miles into the fault line. An underground seismic monitoring station is set up nearby.
Geologists and seismologists probe enormous cracks in the Earth’s crust, so they can see how the plates work and study the internal dynamics. These scientists hope to improve their ability to predict dangerous earthquakes. Researchers at the San Andreas Observatory at Depth noticed changes in the patterns of seismic wave activity prior to earthquakes.
Another process that can cause earthquakes is known as subduction. This process occurs when one tectonic plate slips underneath another. This constant shifting of the Earth’s tectonic plates can increase stress on the crust, which can lead to earthquakes.
Earthquakes are becoming more predictable, yet an effective system of long-term forecasts is still elusive. Researchers are discovering clues by monitoring faults very closely, and they can detect some signals that may suggest an earthquake. For example, the Southern California Earthquake Center says that there is a 46 percent chance that the state will see a 7.5, or greater on the Richter scale, within the next 30 years.
Scientists are gathering more and more information about tectonic plates. They hope that this research will eventually help warn people about dangerous earthquakes.
[Source: Discover Magazine]