Find the center act 1

Find The Center

Plate Tectonics

Compare and Contrast:

1. Continental Crust and Oceanic Crust

2. Lithospheric Plate and Plate Tectonic

3. Primary Waves and Secondary waves

4. Epicenter and Focus5. Seismogram and Seismograph

Recall: Seatwork

Continental and Oceanic

Crust

Lithospheric Plate and Plate

Tectonics

P-waves and S-waves

Epicenter and Focus

Seismogram and

Seismograph

Plate Tectonics

Crust

Continental and Oceanic Upper Mantle

(Asthenosphere)

Lithosphere

in constant but slow motion ARCTIC RIDGE: slowest (less than

2.5cm/yr) EAST PACIFIC RISE near Easter

Island, in the South Pacific about 3,400 km west of Chile : fastest(more than 15cm/yr)

The movement is called TECTONICS

Lithosphere

What are the basis of scientists in dividing the lithosphere in this

manner?

PROCEDURE: Refer to the activity sheets. Write all your answers in a 1 whole sheet of

paper. Complete the table. Copy and Answer Q1 to Q4. Draw the map with the three circles

intersecting or nearly intersecting at a point. The intersection is the EPICENTER.

Act. 1: Find the center.

Table: 560 km; 400 km;

480km Q1. ...epicenter Q2. ...difficulty if only 2

stations Q3. ...distance of epicenter Q4. ...importance of

determining epicenter

Q and A

a method that involves taking seismographic measurements from at least three separate seismic stations. Seismologists measure the time it takes seismic waves to reach the recording stations, as well as the magnitude of the waves, and triangulate the measurements to calculate the location of the epicenter.

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Triangulation

Locating Epicenter: Triangulation

Locating Epicenter:

Triangulation

Philippine Monitoring Stations

Seismologists

P waves travel faster than S wave Because of this difference in velocity

the distance of the epicenter from the recording station can be determined.

Triangulation method is used to determine the exact location of the epicenter.

Remember:

Determining the location

of earthquake epicenters plays a vital role in laying the foundations of plate tectonics.

Remember:

How do you think early

geologists used the plotted positions of earthquake epicenters throughout the world in conceptualizing crustal movements?

But....

Printed copy of

Map of earthquake distribution Map of active volcanoes of the world Map of the Mountain ranges of the world

2 Plastic sheets/cover, same size as your printed map

Marking pens (2 different colors)

Bring: (by group)