Transcript Section 2-2 Measuring Earthquakes

Section 2-2 Measuring
Earthquakes
Erick A. Fernandez
Austin donckels
Miraj S Porter
12-10-07
Focus
• Point beneath Earth’s
surface.
Seismic Wave
• A vibration.
Epicenter
• The surface above the
focus.
• A seismic wave is a
vibration through
Earth releasing energy
Primary Wave
• A p-wave compresses
and expands. Ex: like
an accordion.
Secondary Wave
• Is a vibration from
side to side or up and
down.
Surface Wave
• It moves slower than a
p-wave and an s-wave.
Mercalli Scale
• The Mercalli Scale
rates Earthquakes.
Seismograph
• A Seismograph
records the ground
movement.
Magnitude
• Measures the ground
earthquake.
Richer scale
• Measures the size of a
seismic wave.
Moment Magnitude Scale
• A Moment Magnitude
Scale releases energy.
Seismic Waves
• During an earthquake,seismic waves races out from the
focus in all directions.
• Seismic waves travel like ripples in a pond, they carry the
energy of an earthquake away from the focus through, the
Earth’s interior and across the surface.
• The energy of the seismic wave is greater at the epicenter.
• There are four categories of seismic waves: P waves, S
waves, and surface waves.
• The first waves to arrive are P-waves and S-waves.
Detecting Seismic Waves
• Geologist use instruments called seismographs.
• A seismograph records the ground movement caused by
seismic waves that move through earth.
• recently scientists used mechanical seismograph.
• It consists of a heavy weight attached to a frame by a
spring or wire.
• A pen connected to the weight rest,it’s point on a rotating
drum.When the drum is still the pen draws a straight line
on the paper wrapped around the drum.
• During a earthquake seismic waves cause the drum to
vibrate.
Detecting Seismic Waves
(continued)
• The higher lines on the drum mean the
earthquake is bigger.
Measuring earthquakes
• Magnitude is a measurement of earthquake strength based
on seismic wave and movement along the fault.
• The Mercalli scale is not a precise measurement.
• The richer scale was developed in the 1930s.
• The moment magnitude can be used to rate an earthquake
of all near and far.
• To rate on earthquakes on the moment magnitude
scale,geologist first study data from modern electronic
seismograph.
Locating the Epicenter
• Geologists use seismic waves to locate the earthquake’s
epicenter.
• Seismic waves travel fast. P-waves are the first to arrive at
a seismograph. S-wave’s come close behind.
• To tell how far the seismograph is from the epicenter,
scientist’s measure the difference between the arrival time
of P-wave’s and S-wave’s.
• Geologists draw three circles using data from the
seismograph’s station’s all over the world.
What we learned
• We learned that the Richter scale was
developed in the 1930s.
• Also seismic waves carry the energy of an
earthquake away from the focus to the
epicenter,to the seismograph.
Grade Rubric
for Erick A. Fernandez
• Presentation has title, mentions member’s
names, and includes a complete date.
• Topic slides are well thought out, informative,
full of details, and demonstrate a deep
understanding of the subject.
• Presentation is very creative, animated, and
uses many of the formatting techniques
learned in class.
• Student helped gather the information,
cooperated with the formatting, and helped the
group stay focused by avoiding off-task
behavior.
» TOTAL:
Science
3
3
 20
20
 10
10
7
7
 40
40
Grade Rubric
for Austin Donckels
• Presentation has title, mentions member’s
names, and includes a complete date.
• Topic slides are well thought out, informative,
full of details, and demonstrate a deep
understanding of the subject.
• Presentation is very creative, animated, and
uses many of the formatting techniques
learned in class.
• Student helped gather the information,
cooperated with the formatting, and helped the
group stay focused by avoiding off-task
behavior.
» TOTAL:
Science
3
3
 20
20
 10
10
7
7
 40
40
Grade Rubric
for Miraj Porter
• Presentation has title, mentions member’s
names, and includes a complete date.
• Topic slides are well thought out, informative,
full of details, and demonstrate a deep
understanding of the subject.
• Presentation is very creative, animated, and
uses many of the formatting techniques
learned in class.
• Student helped gather the information,
cooperated with the formatting, and helped the
group stay focused by avoiding off-task
behavior.
» TOTAL:
Science
3
3
 20
20
 10
10
7
5
 40 38
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Teacher Notes
Excellent use of pictures to describe your vocabulary
Great summaries of main ideas
“What we Learned” section needed more thought and details
Nice job with the formatting of the presentation
Science