Please copy your homework into your assignment book BEFORE THE BELL RINGS Please copy your homework into your assignment book Please turn your seismography lab in the orange basket

Warm-up What are three types of Earthquake waves? What is the relationship between the focus and the epicenter of an earthquake?

Monday, December 19, 2016 Warm-up 19.2 notes: Seismic Waves and Earth’s Interior Seismic waves reading and questions Homework: 19.2 Vocabulary and Section Review

Seismic Waves and Earth’s Interior Chapter 19 Section 2 notes

Seismic Waves and Earth’s Interior Scientists who study Earthquakes and earthquake waves are called seismologists. They use instruments called seismometers. Seismometers, or seismographs, are sensitive instruments that detect and record the vibrations sent out by earthquakes.

Seismic Waves and Earth’s Interior

Seismic Waves and Earth’s Interior A seismogram is the record produced by a seismometer.

Seismic Waves and Earth’s Interior Travel-Time Curves Seismologists have constructed global travel-time curves for the initial P-waves and S-waves of an earthquake. For any distance from the epicenter, the P-waves always arrive first.

Seismic Waves and Earth’s Interior The time separation between the curves for the P-waves and S-waves increases with distance. From this separation, the distance from the epicenter of a quake to the seismic facility can be determined.

Seismic Waves and Earth’s Interior Seismic waves change speed and direction when they encounter different materials in Earth’s interior. This fact has allowed scientists to determine what the inside of the earth looks like.

Crust Solid Liquid Solid Plastic-like

Seismic Waves and Earth’s Interior The Earth is composed of 4 main layers Crust – the solid surface of the earth. Mantle – consists of two parts, the upper mantle (lithosphere and asthenosphere) and the lower mantle Outer Core – the liquid part of the Earth’s center. Inner Core – The solid center of Earth made of Iron and nickel.

Seismic Waves and Earth’s Interior SHADOW ZONE is an area on Earth’s surface where no seismic waves are detected. It is a band that goes all the way around the Earth. The shadow zone begins 1050 away from the epicenter of an earthquake and ends 1400 away from the epicenter.

Seismic Waves and Earth’s Interior The actual location of the shadow zone changes based on the location of the earthquake.

Seismic Waves and Earth’s Interior There are two main causes of the shadow zone: 1. P-waves are bent when they hit the liquid outer core. 2. S-waves are totally stopped when they hit the liquid outer core.