1/26/2014 Today’s Schedule: HAZARD UPDATE! Review Lecture 2 Scientific Method Today’s Material Energy Force Hazard vs. Risk Hazards We Will Investigate Earthquakes Group Discussion Class Review Preview Next Class HAZARD UPDATE! • Earthquakes • Any Others? http://earthquake.usgs.gov/earthquakes/eventpage/usb000m8ch#summary
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geol 15 patton lecture 03 - science.earthjay.com · 1/26/2014 The Cascadia subduction zone (CSZ) The following paragraph is a recording from the radio announcer R. Pate, at the radio
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1/26/2014
Today’s Schedule:HAZARD UPDATE!Review Lecture 2
Scientific MethodToday’s Material
EnergyForceHazard vs. RiskHazards We Will InvestigateEarthquakes
1. Observe a phenomenon.2. Formulate an hypothesis.3. Design an experiment to test the hypothesis.4. Perform the experiment.5. Accept, reject, or modify the hypothesis.
What is an example of the Scientific Method in practice?
What causes ice to melt? (or prevents ice from melting)
1. Observe the phenomenon. (e.g. ice melts)2. Formulate a hypothesis. (e.g. ?)3. Design an experiment to test the hypothesis. (e.g. ?)4. Perform the experiment.5. Accept, reject, or modify the hypothesis. (e.g. ?)
What is Energy?
Potential vs. Kinetic?
Energy is the ability to do work. Forms of Energy:
Chemical, electrical, thermal, radiant (light), mechanical, nuclear, etc. Can you think of some examples?
Stored energy is Potential energyMoving energy is Kinetic energyDo you know examples of each?
Can energy change form? Do you know an example?A car uses stored chemical energy in gasoline to move. The engine changes the chemical energy into heat and kinetic energy to power the car.
• A hazard is a situation that poses a level of threat to life, health, property, or environment.
• Do you know of any examples?
What is a Hazard? http://en.wikipedia.org/wiki/Hazard
• Risk is the potential of loss (an undesirable outcome, however not necessarily so) resulting from a given action, activity and/or inaction.
• Can you think of an example where there is a hazard but no risk?
What is Risk? http://en.wikipedia.org/wiki/Risk
• Earthquake• Tsunami• Landslide• Volcano• Flood
What are some potential Hazards?
1/26/2014
The Cascadia subduction zone (CSZ)
The following paragraph is a recording from the radio announcer R. Pate, at the radio station KHAR, who was on duty when the earthquake struck. (Bolt,1978)
"Hey, boy!—Oh‐wee, that's a good one! Hey—boy oh boy oh boy! Man, that's an earthquake! Hey, that's an earthquake for sure!—Whee‐eee! Boy oh boy—this is something you'd read—doesn't come up very often up here, but I'm going through it right now! Man—everything's moving—you know, all that stuff in all the cabinets have come up loose... Who‐eee! Scared the hell out of me, man! Oh boy, I whish this house would quit shaking! That damn bird cage—oooo—oh man! I've never lived through anything like this before in my life! And it hasn't even shown signs of stopping yet, either—ooooeeee—the whole place is shaking—like someone was holding—Hold it, I'd better put the television on the floor. Just a minute—Boy! Let me tell you that sure scared the hell out of me and it's still shaking, I'm telling you! I wonder if I should get outside? Oh boy! Man, I'm telling you that's the worst thing I ever lived through! I wonder if that's the last one of 'em? Oh man! Oh—Oh boy, I'm telling you that's something I hope I don't go through very often. Maa‐uhn!—I'm not fakin' a bit of this— I'm telling you, the whole placed just moved like somebody had taken it by the nape of the neck and was shaking it. Everything's moving around here!—I wonder if the HAR radio tower still is standing up. Man! You sure can't hear it, but I wonder what they have to say on the air about it? The radio fell back here— but I don't think it killed it—Oh! I'm shaking like a leaf—I don't think it hurt it. Man, that could very easily have knocked the tower down—I don't get anything on the air—from any of the stations—I can't even think! I wonder what it did to the tower. We may have lost the tower. I'll see if any of the station come on—No, none of them do. I assume the radio is okay—Boy! The place is still moving! You couldn't even stand up when that thing was going like that—I was falling all over the place here. I turned this thing on, and started talking just after the thing started, and man! I'm telling you, this house was shaking like a leaf! The picture frames—all the doors were opened—the dishes were falling out of the cabinets—and it's still swaying back and forth—I've got to go through and make a check to make sure that none of the water lines are ruptured or anything. Man I hope I don't live through one of those things again...."
What are earthquakes?Earthquake is a term used to describe both sudden slip on a fault, and the resulting ground shaking and radiated seismic energy caused by the slip, or by volcanic or magmatic activity, or other sudden stress changes in the earth.
EarthquakeAnimation shows the buildup of stress along the margin of two stuck plates that are trying to slide past one another. The rock is deformed as it builds up strain in the plates; stress increases along the contact.
Earthquake with treesAnimation of above adds trees to emphasize motion after the fault slip. At this scale, all the trees would shake, but here we only show shaking of the trees that were on the deforming parts of the plates immediately adjacent to the fault.
http://www.youtube.com/watch?v=xSbKnq2ji5M&feature=player_embeddedReal Earthquake with real treesActual video footage of a grove of oak trees taken by a USGS camera on Sep. 28, 2004. The camera, stationed along the San Andreas Fault, is part of a monitoring effort to increase our understanding of earthquake behavior. This camera records a snapshot image every 5 minutes until ground motion triggers the video camera to record continuously. About 6 seconds into the clip the M 6.0 Parkfield earthquake shakes the ground.
Stress and Strain (Energy Transfer): What is stress and what is strain? How do these relate to earthquakes?
Additional resources:
Stress: Tension vs. Compression vs. ShearTensional stress is the stress that tends to pull something apart. It is the stress component perpendicular to a given surface, such as a fault plane, that results from forces applied perpendicular to the surface or from remote forces transmitted through the surrounding rock.Compressional stress is stress that squeezes something. It is the stress component perpendicular to a given surface, such as a fault plane, that results from forces applied perpendicular to the surface or from remote forces transmitted through the surrounding rock.Shear stress is the stress component parallel to a given surface, such as a fault plane, that results from forces applied parallel to the surface or from remote forces transmitted through the surrounding rock.
Image courtesy of Michael Kimberly, North Carolina State Univ.
http://earthquake.usgs.gov/learn/glossary/
1/26/2014
What is strain?Strain is the relative change in shape or size of an object due to externally‐applied forces (e.g. stress).
Hooke’s Law: Stress is directly proportional to strain. >>>>>>>>
http://en.wikipedia.org/wiki/Hooke%27s_law
What does “elastic” mean?Elastic refers to internal strain in a material. This internal strain is observed as a distortion of the material. Elastic deformation returns to it's original shape after a strain is applied.
What does “plastic” mean?Plastic refers to internal strain in a material. This internal strain is observed as a distortion of the material. Plastic deformation stays in the deformed shape after a strain is applied.
Group Discussion:
• What Hazards are also Risks to us on the Northcoast?
• Why?
Class Review:Review Recent Hazards (e.g. earthquake list)Cover Material/Objectives
EnergyForceHazard vs. RiskHazards We Will InvestigateEarthquakes
1/26/2014
One Minute Paper, that lasts three minutes.
I want to read about what you do understand. What is the most exciting thing you learned today?
I want to read about what you do not understand. What may have been confusing?
What is one question that you have about today’s lecture?
We will cover these issues during our review of today’s class at the beginning of our next class.
Next Class:
• Stress and Strain (energy transfer)• Sliding Brick / Elastic Rebound Activity• First Pop Quiz (email me tonight with
your personal information and I will provide you a special clue for the quiz).
• Name• Why are you taking the class?• What is your goal at College of the Redwoods?• What is the highest level of math you have taken?• How will you use what you learn in this class in your
daily life?• What is the most important natural hazard (as it
relates to you and your life)?• Have you experienced any natural hazards? If so, do
you have a story to tell? Please tell me your story.