Print this page Great Earthquakes and Associated Tsunamis
Samir G. Khoury, Ph.D., P.G.
Course Outline
The introduction of the course starts by presenting the type and distribution of the seismic instruments that were deployed throughout Japan at the time the Tohoku-oki earthquake occurred. Following a presentation of the characteristic parameters of the earthquake and its aftershocks, the presentation unfolds by addressing the following topics:
Cause of the Great Japan Tohoku-oki Earthquake
Manifestation of Earthquakes
Types of Seismic Waves
Body Waves
Surface Waves
Travel Times of Seismic Waves
Interior Structure of the Earth
Propagation of the Great Tohoku-oki Earthquake
Cascading Effects
Tsunami Initiation
Tsunami Propagation
Near Shore Amplification of Tsunami Waves
Sequence of Events
Tsunami Effects on Fukushima Daiichi
How can you protect against a Tsunami?
Finally the course concludes with an Appendix that presents the derivation of seismic wave velocities and a glossary of terms and acronyms used in the course to assist the student in following the concepts that are discussed.
This course includes
a multiple choice quiz at the end,
Learning Objective
At the end of this course you should be able to understand the causes that unleash these catastrophic natural phenomena. A sudden sea-floor displacement triggered this massive earthquake and generated a monstrous tsunami that devastated hundreds of kilometers of coastline along the islands of Honshu and Hokkaido. You will also learn about:
- The characteristics of great earthquakes;
- The forces within the earth that generate such disasters;
- The types of seismic waves that are generated by earthquakes;
- The laws that govern the propagation of seismic waves;
- The travel times of seismic waves;
- The interior structure of the earth;
- The paths of seismic waves through the earth;
- The mechanisms that lead to the initiation and amplification of tsunamis;
- How tsunamis are detected, tracked and their propagation forecasted;
- The tsunami effects on the nuclear power plants at Fukushima Daiichi;
- The sequence of events that led to the nuclear accident; and
- The most efficient way to protect against a tsunami.
Intended Audience
This course is intended for geologists, engineers, scientists, geotechnical engineers, engineering geologists, other interested individuals and the general public who are curious and want to learn about the deep seated geological processes that shape the surface of our planet.
Benefit to Attendees
This course is presented as a complement to courses G-175 Earthquakes: Basic Principles and G-207 Tsunamis: Basic Principles. It was prepared for students who want to learn more about the internal structure of the earth and what causes these devastating events. On the other hand, this course was also prepared as a standalone presentation that can be taken independently of the other two courses.
Course Introduction
One of the great tragedies of modern times occurred in March 2011, hitting the Northeast Coast of Japan abruptly and with very little to no advance warning. This disaster came in the form of an earthquake so powerful that it knocked the earth off its axis of rotation. This great earthquake also spawned a tsunami so overwhelming that it literally wiped out several coastal towns in Northeast Japan. This tsunami encroached inland for distances of up to 5 or 6 kilometers drowning and destroying everything in its path. It was estimated that this earthquake was the largest one to strike Japan in a thousand years.
What forces within the earth generated this epic disaster? Because Japan is so well monitored by automated sensing instruments scientists have been able to accumulate a wealth of real time data about this event, thus enabling them to reconstruct and know exactly what happened. Every detail of this tragedy was recorded real time by seismometers, Global Positioning System (GPS) instruments, strain gauges and tidal gauges. For example, to monitor earthquakes, the Japan Meteorological Agency (JMA) operates a uniquely dense earthquake observation network comprised of over 200 seismographs/seismometers. In addition, the Agency operates over 600 seismic intensity meters. It also collects data from over 3,600 seismic intensity meters managed by local governments and the National Research Institute for Earth Science and Disaster Prevention (NIED).
The data thus collected are input into the Earthquake Phenomena Observation System (EPOS) at the Agency’s headquarter in Tokyo and at the Osaka District Meteorological Observatory on a real-time basis. The following figure gives a visual impression of the dense distribution of seismic monitoring devices throughout Japan.
Course Content
The course content is in the following PDF file:
Great Earthquakes and Associated Tsunamis
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Course Summary
At the end of this course you should be able to understand the causes that unleash these catastrophic natural phenomena. A sudden sea-floor displacement triggered this massive earthquake and generated a monstrous tsunami that devastated hundreds of kilometers of coastline along the islands of Honshu and Hokkaido.
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
