What is Seismology?
Seismology is a young science. Although people have been interested in earthquakes for many hundreds of years, the roots of modern seismology date back only about 100 years to the development of the first instruments capable of recording earthquake (seismic) waves. The scientists who developed the first seismometers were initially interested in studying earthquakes. During the twentieth century the scope of seismology broadened to include the investigation of the Earth's interior using waves from earthquakes as well as other sources.
Modern seismology has become a multifaceted discipline that focuses on issues of both scientific and societal concern. Investigation of earthquakes as a physical process has yielded many important insights about the phenomenon. However, many very fundamental questions about earthquakes remain unanswered: How do earthquakes start? What controls their timing? How do they stop? Although most seismologists are pessimistic about the possibility of predicting earthquakes, a better understanding of fundamental processes ("earthquake physics") will allow us to improve our assessment of earthquake hazard.
One important subfield of modern seismology is known as "ground motion seismology." Ground motion seismologists work to understand and predict the shaking that is generated by large earthquakes. Such efforts can then guide engineering and building practices so that structures can be made earthquake-resistant. In the immediate aftermath of a large earthquake, maps of the distribution of strong shaking are also now made available to disaster officials to aid in the relief efforts.
Another important subfield of seismology involves the determination of the locations and times of the thousands of earthquakes that occur each year. These include both moderate to large earthquakes that are recorded over great distances and small earthquakes that can be detected only locally. Analysis of large earthquakes is typically done in observatories or analysis centers built around large computers and supported by national governments. Smaller earthquakes are typically processed at regional research centers that are part of university or government laboratories.
The accurate determination of the place and time of an earthquake requires detailed knowledge of the internal structure of the Earth. Much of what is known about the Earth's interior, from the uppermost crust to the central core, has been learned by painstaking analysis of the waves generated by earthquakes and, recently, by large explosions that are recorded by seismographs.
After decades of observations of earthquake locations, seismologists have been able to determine the locations at which earthquakes occurred most commonly in the past--and therefore are expected to be most likely in the future. This information is also vital to the task of earthquake hazard assessment. Again, while considerable progress has been made, fundamental questions remain unanswered. Large earthquakes do not always occur where they are expected, and sometimes expected earthquakes do not occur "on schedule."
Some lines of seismological research are more applied in their focus than others, but the distinction between pure and applied research tends to blur. By striving to understand the physical nature of the Earth and the processes associated with earthquakes better, seismologists will continue to improve our understanding of earthquake hazard as well.
The most important commercial application of seismology is in the search for oil, and large numbers of seismologists are employed in the petroleum industry. The same basic principles that enable a seismologist to explore the interior of the whole planet using earthquake waves can be applied on a much smaller scale to the detailed mapping of subsurface structure in a limited region. These studies use waves generated by small explosions or mechanical devices. Geological conditions favorable for the accumulation of oil, not detectable from surface evidence, can be found in this way.
An application of seismology of great importance to world peace is the monitoring of underground nuclear explosions. Nuclear explosions generate seismic waves that can be recorded at large distances. Seismic observations provide the best method now known for determining whether or not foreign countries are complying with test ban treaties.
How do I become a Seismologist?
Research seismologists come into the field with a wide variety of undergraduate majors. Only a few universities offer undergraduate degrees in geophysics, of which seismology is a part. Because seismology is an applied field, most graduate departments prefer students to have solid undergraduate training in more basic disciplines, particularly mathematics or physics. Coursework in basic geology is also very helpful, as is expertise with computers. The computer is the primary tool of the trade for most research seismologists, so a high degree of computer expertise is essential.
As in all the physical sciences, preparation for a research career, whether in a university, private industry, or with the government, requires the completion of a Ph.D. degree. However, rewarding careers in observational and operational seismology, especially in the petroleum industry, are open to holders of a Bachelor degree. Many have found that a Master of Science degree in geophysics, providing a year or two of advanced specialized study before beginning an industrial career, is a valuable asset.
A student's choice of undergraduate major and graduate school program should be geared to particular interests within the field. A great deal of information is now available via the World Wide Web, including general information (see links below) as well as information about specific university departments. Undergraduate students who are interested in pursuing a graduate degree in seismology are also encouraged to talk to their math and science professors. In many cases, professors will be aware of opportunities such as undergraduate internships that can provide invaluable experience and training.
IRIS (Incorporated Research Institutions for Seismology)
(institutions with seismology programs)
U.S. Geological Survey
(employs many seismologists and geologists)
Comprehensive Test-Ban Treaty Organization
Society of Petroleum Engineers
American Geological Institute
(federation of geoscience organizations)
American Geophysical Union
Geological Society of America