Earthquake Machine
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Earthquake Machine Mechanical Modeling to Increase Student Understanding of Complex Earth Systems Michael Hubenthal - IRIS Consortium
description
Earthquake Machine. Mechanical Modeling to Increase Student Understanding of Complex Earth Systems. Michael Hubenthal - IRIS Consortium. Objectives (SWBAT). Explain earthquakes as a part of the natural Earth System Describe global trends for Earthquake occurrence and magnitude - PowerPoint PPT Presentation
Transcript of Earthquake Machine
Earthquake Machine
Mechanical Modeling to Increase Student
Understanding of Complex Earth Systems
Michael Hubenthal - IRIS Consortium
Objectives (SWBAT)Explain earthquakes as a part of the natural Earth System Describe global trends for Earthquake occurrence and magnitudeInterpret a Gutenberg Richter plot (Frequency vs. Magnitude)Critically analyze an argumentDescribe the importance of sharing science results with peers in the science process
Write down a definition for an earthquake
What is an Earthquake?
In small groups, discuss your definitions of an earthquake and create a consensus definition
Exp
lori
ng w
ith
a m
odel
…
B
C
EQ Machine - Lite
Top View
Bulk of the Plate
Edge of the Plate
Elastic Properties of Earth Materials Plate has
Constant Velocity Here
How would you alter your definition, to accommodate these observations?
What did you observe?
Distant forces cause a gradual build up of stress in the earth over tens or hundreds or thousands of years, slowly distorting the earth underneath our feet. Eventually, a pre-existing weakness in the earth--called a fault or a fault zone--can not resist the strain any longer and fails catastrophically.
Elastic Rebound Theory
http://quake.wr.usgs.gov/research/deformation/modeling/animations/index.html
Key Concepts Elastic materials can store potential energyEarth materials are elastic though they may not seem it within our temporal and thermal scalesThe Earth’s plates are constantly in motion though we can not perceive this without instruments
Studying Earthquake Recurrence
Developing arguments….
How many beads are in the box????
Exp
lori
ng w
ith
a m
odel
…
Seismic MomentMo = fault length x fault width x displacement x rigidity
Moment Magnitude = Mw = log Mo/1.5 – 10.7
Seismic MomentMo = fault length x fault width x displacement x rigidity
Visualizing magnitude with the model
B
Moment Magnitude = Mw = log Mo/1.5 – 10.7
Group A“There are long periods of quiet
between earthquakes”
Develop an argument* either for or against this statement based on your experimentation with the earthquake machine.
*Note: You must base our argument on minimally 30 events
“Most earthquakes are huge, deadly and
destructive events”
Group B
Earthquake Frequency
0
5
10
15
20
25
1-2 Years 3-4 Years 5-6 Years 7-8 Years 9-10Years
11-12Years
13-14Years
15-16Years
Time Between Events
Earthquake Count
Count
“There are always long periods between earthquakes.”
Earthquake Size Distribution
0
2
4
6
8
10
12
14
16
18
20
0-1.99 2-3.99 4-5.99 6-7.99 8-9.99 10-11.99
12-13.99
14-15.99
16-17.99
18-19.99
20-21.99
22-23.99
24-25.99
26-27.99
Magnitude (Slip CM)
Count Earthquake
Frequency
“All earthquakes are huge, deadly, and destructive events”
Components of Prediction
When?Where
How Big?
Using the data you have collected argue either for or against the following statement…
“There hasn’t been an earthquake in a long time; therefore the next one must be huge.”
Frequency/Magnitude Relationship
2.7 2.84.1
5.3
7.38
12.6
3.6
27.8
0.7 1 0.71.7
4.4
8
12.6
3.6
27.8
1.5 1.82.7
3.9
6.3
8
12.6
3.6
27.8
0
5
10
15
20
25
30
1 2 3 4 5 6 7 8 9
Years Between Events
Magnitude (Slip CM)
Characteristic
Time Predictabl
e
Slip Predictab
le
Stress
Slip
Time
Calaveras Fault Data
(Bufe et al., 1977)
For a full description of the EQ Machine and a multi-period lab please visit:
http://www.iris.edu/edu/lessons.htm
Young students ideas
(Ross and Shuell, 1991)
(Leather, 1987)
(Tsai, 2001)
Conceptual shift at age 14?
(Barrow & Haskings, 1996; DeLaughter et al., 1998; Libarkin et al., 2005))
Location of EQs & relation to plates
During the 1906 event the earth on one side of the fault had slipped compared to the earth on the other side of the fault by up to 21 feet (7 m).
Centennial Connections
Steinbrugge Collection of the UC Berkeley EERC
After studying the fault trace of the 1906 earthquake and regional surveys (pre/post event), Harry Fielding Reid, postulated that the forces causing earthquakes were not close to the earthquake source but very distant.
Examine page one of your data set and
develop a prediction for the 26th event
based on the previous 25 events.
Event #
Time Displacement
0
2
4
6
8
10
12
14
Time (Years)
Displacement (cm)
Seismicity of the EQ Machine - 67 “Years”
0
5
10
15
20
25
30
Seismicity of the EQ Machine - 163 “Years”
