Earthquakes by Claire Chadney

Environmental Studies
PHS 100
Warner Pacific College
October 12, 2010

Every morning we wake up, get dressed, and head out to start our day never expecting that day to be short-circuited by a natural disaster. We come home from our days and turn on the news to see floods, fires, drought, hurricanes, tornadoes, and earthquakes; but assure ourselves that we are safe from harm. Still, just to be sure, we buy flood insurance, build our homes with steel and concrete, and set up emergency evacuation plans.
Why do we do this? Because natural disasters do happen, and they can happen anywhere and anytime. Some natural disasters, such as hurricanes, allow us time to prepare; but others, including flash flooding, tornadoes, and fire do not always give us fair warning.
Earthquakes differ from most natural disasters because we have developed technology that can help predict where seismic activity will occur. The idea of plate tectonic theory was first proposed by Albert Wegener in 1915. Wegener had noticed that the continents appeared to have drifted over time and continents looked to be broken off pieces of one continent. While much of the content of Wegener’s “continental drift” theory was later disproven, he was able to bring the idea of “crustal movements” to the scientific community. Paleontologists were also able to provide physical evidence that supported the theory of plate tectonics as they began to discover similar fossils on continents that were separated by many thousands of miles. Studies of the Earth’s previous magnetic field and climate changes over time also lent their support to this theory (Glasscoe).
The largest evolution in the development of understanding of earthquakes and tectonic plates came following World War II. Many governments world-wide feared nuclear weapons and placed seismometers in the ground to monitor any nuclear testing. Unexpectedly, these seismometers revealed that earthquakes, volcanoes, and other active geologic features tended to follow distinct belts around the world. Those belts defined the edges of the tectonic plates (Glasscoe).
Seismography has remained a critical tool in evaluating the magnitude and depth of earthquakes. Defining where these tectonic plates lie has made it much easier to determine where earthquakes are expected to happen. Determining when an earthquake will happen has proven to be much more difficult. Science has not developed enough to be able to provide predictably accurate timelines for earthquake and volcanic activity.
Because many thousands of years can occur between periods of significant fault activity, humans have continued to inhabit areas that are susceptible to earthquakes. As we all have witnessed on the news, these fault areas can become active and earthquakes can rip through homes and lives in a matter of minutes.
On March 25, 1993, I experienced my very first earthquake. The earthquake epicenter was located near Scotts Mills, Oregon; approximately 20 miles from my home in Gervais, Oregon. The quake occurred at 5:34 in the morning and was a 5.6 in magnitude. The magnitude of this earthquake placed it as the most significant earthquake in the Pacific Northwest since 1981. There were no human casualties associated with the earthquake, a fact that scientists attribute to the early morning hour that the quake occurred. Damage was limited to minimal structural damage to nearby homes, schools, and the State Capitol building in Salem.
That morning I was awakened by an intense shaking of my home, which initially I believed was nothing more than a train passing on the nearby rail. Very quickly though, I realized my mistake as a picture at the head of my bed crashed to the floor. My father threw open my bedroom door and herded myself and my brother down the stairs of our 1906 Victorian home. Pausing on the way down the stairs, my brother and I noted how the stairs seemed to ripple and rise, shaking plaster from the ceiling and jamming doors that had opened easily the day before. We rushed to the first floor and took cover in a doorway for the next several minutes. Once the quake passed, an evaluation of our home showed minor foundation cracks and several fallen objects, but no real damage.
This earthquake was a wakeup call to my family and neighbors. We no longer took for granted that the land our homes stood on was invulnerable. We realized all that we had worked for could be swept away in moments. Scientists will continue to strive to understand the nature of earthquakes and other seismic changes in order to be able to prevent the property and life damage that can occur in an earthquake, but for now we all need to realize just how delicate a precipice we live on and how quickly our world can be torn from underneath our sleeping heads.

References
Glasscoe, Maggi, The Southern California Integrated GPS Network Education Module, History of Plate Tectonics, October 10, 2010, http://scign.jpl.nasa.gov/learn/plate2.htm

United States Geological Survey, The Science of Earthquakes, October 10, 2010, http://earthquake.usgs.gov/learn/kids/eqscience.php

Ludwin, R.S., A.I. Qamar, S.D. Malone, R.S. Crosson, S. Moran, G,C. Thomas, and W.P. Steele, Scotts Mills Earthquake Summary, October 10, 2010, http://www.pnsn.org/SEIS/EQ_Special/ScottsMills/scottsmills.html