Chapter Goals–
Interpret types, causes, effects, and scientific measurements of earthquakes and seismic waves

Introduction

In the last chapter we looked at rocks being BENT and BROKEN (folded and faulted).
Sometimes, faulting generates a rapid push or “shove” into the surrounding material.  That bump into the adjoining rocks creates a seismic wave.  If you want, you can be a human seismometer by simply putting your ear on the table, and giving it a tap with your knuckle a couple feet away.  The sound that you hear coming through the table is a P-wave (quite similar to the sound waves that you hear coming through the air).  More on seismic waves to come!

Have you ever wondered why California or Japan has so many earthquakes? Have you ever been in an earthquake and felt the solid ground shake beneath your feet?

Imagine you are going about your normal routine for the day and it is time for you to wrap up your day to head home. As you start gathering your things to take home and work your way out to your car, the following happens:

https://youtube.com/watch?v=jBdvvXyS-r4%3Fenablejsapi%3D1

This earthquake measured a 9.0 on the Richter scale and was the most powerful earthquake to hit Japan and the fourth most powerful recorded by humans. Aftershocks numbered over 1,000, with some over a 6.0 on the Richter scale. Almost 16,000 people died, over 6,000 were injured, and 2,500 were missing. The earthquake also damaged a nuclear facility causing major radioactive leaks. The World Bank estimated the economic cost of damage at $235 billion!

Once the shaking subsided, the following happened:

Learning Outcomes

• Investigate the causes and common locations of earthquakes
• Compare and contrast properties and mechanics of different types of waves
• Define and compare magnitude versus intensity.
• Understand the hazards of earthquakes and recognize our limited ability to predict seismic activity.