Warm up 9/29 1) What is convection flow and how does this lead to movement of lithospheric plates? 2) What creates convection flow? 3) Draw a diagram of convection flow. Label the parts in your diagram.

1 st block, 9/30 1. Finish reading the Haiti Earthquake article and answering the questions 2. Hand it in the black box when finished. 3. You have 20 minutes

Warm-up 9/30, 4 th block List the three types of seismic waves and describe one characteristic of each type. List the three types of seismic waves and describe one characteristic of each type. Put your name on this sheet of paper and hand it in the black box up front. Put your name on this sheet of paper and hand it in the black box up front.

Objectives

First…table of contents! 5 DateTitlePage 9/22/14Convection currents and Plate Tectonics Guided Notes with Vocabulary 1 9/22/14Plate Boundaries Diagram 2 9/22/14Tectonic Plates Activity Sheet 3 Unit 2: Earthquakes & Plate Tectonics 9/29/2014Volcanoes and Earthquake Anatomy Notes 4

Volcanoes A volcano is mountain formed of lava and/or pyroclastic material A volcano is mountain formed of lava and/or pyroclastic material

Convergent boundaries They can be caused by convergent boundaries, in which plate subduction forces magma to the surface. They can be caused by convergent boundaries, in which plate subduction forces magma to the surface.

Divergent Boundaries Volcanoes are also formed by divergent boundaries because as plates move apart, magma rises to fill the gap. Volcanoes are also formed by divergent boundaries because as plates move apart, magma rises to fill the gap.

Magma vs. Lava Magma is molten rock found beneath the Earth’s crust Lava is molten that reaches the surface and erupts from the volcano

Effects of volcanoes 1) Lahar- material that flows down the volcano. It is a mixture of water and rock fragments

Effects of volcanoes 2) Volcanic ash: fragments of material that explode from the erupting volcano

What happened in Japan? Tsunami hitting the coast: Tsunami hitting the coast: 8jK4ci2g 8jK4ci2g 12

The red dots are locations of Earthquakes. Make an observation and an inference about this map.

San Francisco 1989 SF Earthquake 1989 (longer) SF Earthquake 1989 (longer) SF Earthquake 1989 (longer) SF Earthquake 1989 (longer)

What is a focus? The point beneath the Earth’s surface where rock under stress breaks to cause an earthquake.

What is an epicenter? The point on the surface directly above the focus.

The farther the distance between the focus and the epicenter, the weaker the earthquake. Therefore, the closer the focus is to the surface, the stronger the earthquake.

Distance from Focus to Epicenter

What is a fault? It is the break in the crust where the earthquake began, between two blocks of rock that have moved past each other.

3 Types of Faults NormalReverseStrike-slip When the hanging wall drops down. When hanging wall moves up. Walls move sideways Creates forces that pull the sides apart Creates compressional forces. Horizontal forces

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Quick Review 1)What causes an earthquake? 2)Label the fault, epicenter, and focus in the picture to the right. A = B = C = a b c

What are seismic waves? Seismic waves are the waves (vibrations) caused by earthquakes

During an earthquake, vibrations called seismic wave move out from the focus in all directions similar to the ripples created by a pebble in a pond.

Seismic waves carry the energy of an earthquake away from the focus, through the Earth’s interior, and across the surface.

What are the three types of seismic waves? Primary waves Primary waves (P waves) (P waves) Secondary Waves Secondary Waves (S waves) (S waves) Surface waves (L waves) Surface waves (L waves)

Describe a P wave. Travel the fastest Travel the fastest Travel solids, liquids, and gases Travel solids, liquids, and gases Move through the Earth at different speeds, depending on the density Move through the Earth at different speeds, depending on the density Called “push-pull” waves (compress and expand the ground like an accordion) Called “push-pull” waves (compress and expand the ground like an accordion)

Describe an S wave. Arrive at a given point after the Arrive at a given point after the P waves P waves Travel only through solids Travel only through solids Move through solids at different speeds depending on the density Move through solids at different speeds depending on the density Cause rock particles to move from side to side & up and down Cause rock particles to move from side to side & up and down

Describe a L wave. Slowest of the seismic waves Slowest of the seismic waves Move along the Earth’s surface like waves travel in the ocean Move along the Earth’s surface like waves travel in the ocean Cause most of the damage during an earthquake Cause most of the damage during an earthquake

When the P & S waves reach the surface, they move more slowly creating the most severe ground movements.

What do scientists use to detect and measure earthquakes? Seismographs are used by scientist to detect, measure & record the vibrations of seismic waves. An earthquake’s magnitude is a measurement of its strength based on seismic waves and movement along faults.

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Seismic Wave Demo

EQ & Seismic Wave Foldable Let’s Fold and Label together Let’s Fold and Label together The directions for the inside of the foldable is at your station The directions for the inside of the foldable is at your station

What are 3 rating scales used to measure an earthquake?

Mercalli scale – This scale rates earthquakes by describing their effects on people, buildings, and the land surface in a given location.

Richter scale This scale rates earthquakes according to the size of seismic waves as measured by the seismograph.

Moment Magnitude scale This scale rates earthquakes by estimating the total energy they release. The moment magnitude scale can be used to measure earthquakes of all sizes, near or far!

How do scientists determine the location of an earthquake’s epicenter?

When an earthquake strikes, P waves are the first to arrive at a seismograph followed by the S waves. When an earthquake strikes, P waves are the first to arrive at a seismograph followed by the S waves. The farther away the epicenter is, the greater the difference between the two arrival times. The farther away the epicenter is, the greater the difference between the two arrival times.

This difference in time tells scientists how far the seismograph is from the epicenter. This information is then used to plot a circle on a map.

The circle shows the distance from one seismograph station to all points where the epicenter could be located.

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To determine the exact location of the epicenter, at least THREE stations need to find their distance from the epicenter and draw a circle on a map To determine the exact location of the epicenter, at least THREE stations need to find their distance from the epicenter and draw a circle on a map

The single point where the 3 circles intersect is the location of the earthquake’s epicenter.

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