The eLearning Center for Gatlin Education Services

Overview

This course introduces you to the fundamental concepts about earthquakes. Following a brief narrative of the myths and mystery that surrounded the occurrence of earthquakes throughout history, the course describes the precise effects of the first major earthquake recorded in the mid-eighteenth century. This initial advance led to the development of the new discipline of seismology in the nineteenth century, and by the late nineteenth century sufficient progress had been made to develop standardized scales to characterize the shaking severity of earthquakes. With the advent of the twentieth century and the development of instruments that capture and record the ground motion generated by earthquakes, it became possible to eventually develop the Richter magnitude scale.

The intensity of shaking as a measurement scale is presented: the Rossi-Forel and the Modified Mercalli scales. An explanation is given as to why these scales are not entirely satisfactory for measuring the absolute size of earthquakes. The discussion about the modern magnitude scale covers its use as a measurement of earthquake size and as an index of the energy released at the source of an earthquake. The association between faults and earthquakes is explained and the geometrical relationship between the fault plane, the hypocenter (or focus) and the epicenter of an earthquake is illustrated.

The major earthquakes that have affected North America, namely the 1811 New Madrid, Missouri, the 1886 Charleston, South Carolina, and the 1906 San Francisco, California, earthquakes are described. The intensity of the ground shaking associated with these three earthquakes is presented in a figure that clearly shows that at the same intensity level, the shaking effects extend over a much larger area in the Eastern United States than in the Western United States.

The great 1964 Prince William Sound, Alaska earthquake is described because of its very large magnitude and because it disturbed the ocean floor generating immense sea waves called “tsunamis”, a Japanese word for “huge wave”. These waves devastated coastal towns around the Gulf of Alaska and along the western coast of North America. The tsunami waves traveled across the Pacific Ocean at great speed reaching the islands of Hawaii and Japan causing damage there too. Information about the Great Southeast Asia Earthquake and Tsunami of 2004 is also presented and discussed. This 2004 tsunami was one of the largest ever in terms of casualties because it hit heavily populated low-lying coastal areas in many countries that were completely unprepared.

Finally, the equations used to derive the Richter magnitude of an earthquake and compute the energy released during that earthquake are presented in an Appendix. Also, a glossary of terms and acronyms used is provided as a reference to assist the student in following the concepts that are discussed throughout.

The information presented in this course is based on the professional experience gained by the author over more than thirty-five years of dealing with various aspects of seismic issues associated with the major engineering projects he managed around the world. Subsequent courses will deal with additional aspects of earthquake studies (such as detection, location, and the nature of ground motion) and the advances that led to a fuller understanding of the structure of the earth.

The student must take a multiple-choice quiz consisting of seventeen (17) questions at the end of this course to earn PDH credits.

Specific Knowledge or Skill Attained

At the end of this course, you should be able to understand how the scientific knowledge about earthquakes was developed. You will also learn how the severity and size of earthquakes are determined using:

  · The Rossi-Forel Intensity Scale
  · The Modified Mercalli Intensity Scale, and
  · The Richter Magnitude Scale

You will learn about faults and should be able to understand the geometrical relationship between the fault plane, the hypocenter (or focus) and the epicenter of an earthquake. You should also be able to follow the basic concepts behind:

  · The seismograph (an instrument used to capture and record the ground vibrations that accompany an earthquake)
  · The seismogram (the permanent record of an earthquake as recorded by a seismograph), and
  · The basic equations that are used to compute the Richter magnitude and the total energy released during an earthquake

Finally you will learn about the major earthquakes that have affected North America and their effects over large areas. You will also learn that large earthquakes that affect the ocean floor are capable of generating immense sea waves called “tsunamis”, a Japanese word for “huge wave”. These tsunami waves can travel across oceans at great speed inflicting significant damage to distant coastal towns.

State Board Acceptance

This course can be used by professional engineers to fulfill PDH requirements mandated by state and provincial licensing boards. Decatur Professional Development is an approved provider of continuing education in all states that pre-approve course providers. In all other states that mandate continuing education for engineers, it is the individual engineer's responsibility to determine the suitability of activities for PDH credit. The state boards typically accept online* courses that cover technical, managerial** or ethical content and which are relevant to the practice of engineering. The course must have a clear purpose or objective with a content that will maintain, improve or expand the skills and knowledge of the licensee’s field of practice. For questions about your mandatory PDH requirements, visit the website of your state licensing board.

*Online courses are accepted by all state licensing boards that mandate continuing education. Other than New York (which limits online courses to 18 PDH) and Iowa (which limits online courses to 6 PDH), there are no limits placed by other states on the number of hours that can be earned through online continuing education. Consult with your state licensing board if you have any questions about the acceptability of online courses.

**The New York State Board of Engineers does not accept general office management courses, but will accept project management courses that are offered by an approved provider and that are technical in nature and contribute to the engineer's professional practice.