Transcript Section 19.2 Day 1

EXTRA CREDIT
OPPORTUNITY!
1. Attend the musical this
weekend.
2. Get the program signed by a
cast member.
3. Bring it to class next week.
4. Earn 10 EXTRA CREDIT
POINTS!
Thursday, May 6th
Agenda
Collect homework: “High Up in the
Himalayas” worksheet
Quiz over section 19.1
Begin Section 19.2: Earthquakes and
Volcanoes
Movie: “Earthquakes: Our Restless Planet”
Homework: “Plinian Eruptions” Worksheet
We will finish section 19.2 next time…
Section 19.1: Earth’s Interior and Plate
Tectonics Walk/Talk Quiz
 Answer only the question that corresponds with
your birthday month.
 Once everyone has answered their 1 question,
get up, walk and talk with your classmates to
complete the rest of the quiz.
 Don‘t just copy their answer, read the question,
answer it yourself and see if you agree.
 If you don’t, discuss it and try to come up with
the correct answer together. Good Luck!
What are Earthquakes?
Earthquakes occur at plate boundaries.
Earthquakes are vibrations resulting from
rocks sliding past each other at a fault
Seismic waves are waves of energy released
during in earthquake
Focus the area along a fault at which the
first motion of an earthquake occurs
Epicenter the point on Earth’s surface
directly above an earthquake’s focus
What are Earthquakes? continued
 Energy from earthquakes is transferred by waves.
Earthquakes generate three types of waves:
Longitudinal waves
Transverse waves
Surface waves
 Longitudinal waves travel by compressing and
stretching crust, also called primary waves (P
waves)
 Transverse waves travel in an up and downward
movement, also called secondary waves (S
waves)
 Surface waves seismic waves that can move only
through solids, move in a rolling circular motion
What are Earthquakes? continued
Waves move through Earth and along its
surface.
Both P waves and S waves spread out from
the focus in all directions through the earth.
Surface waves move only on Earth’s
surface.
Measuring Earthquakes
Seismologists detect and measure
earthquakes.
Seismology the study of earthquakes
including their origin, propagation, energy,
and prediction
Seismologists use sensitive equipment called
seismographs to record data about earthquakes.
Measuring Earthquakes, continued
Three seismograph stations are necessary to
locate the epicenter of an earthquake.
There are more than 1000 seismograph
stations across the world.
Because P waves travel faster, the
difference between the arrival of P waves
and the arrival of S waves allows scientists
to calculate how far away the focus is.
Measuring Earthquakes,
continued
Geologists use seismographs to investigate
Earth’s interior.
The way P and S waves travel through Earth’s
interior help scientists make a model of Earth
with layers of different densities.
Measuring Earthquakes,
continued
The Richter scale is a measure of the
magnitude of earthquakes.
Richter scale a scale that expresses the
magnitude of an earthquake
The intensity of an earthquake is measured by
the modified Mercalli scale. Intensity depends
on many factors.
Earthquakes that occur deeper below the
Earth’s surface will not be as intense at the
surface.
The hardness of the rock above and around an
earthquake affects the intensity.
Measuring Earthquakes,
continued
Scientists are trying to predict earthquakes.
Scientists are trying to measure changes in
Earth’s crust that might signal an earthquake.
The ability to predict an earthquake could
save thousands of lives in the future.
Movie:
“Earthquakes: Our Restless Planet”
Homework:
– “Plinian Eruptions” Worksheet
Have a GREAT
weekend!!