Earthquake Wave Modeling Lab

Let's take a few moments to talk about how we're going to talk... so to speak.

The prelab for this earthquake lab is absolutely critical, and quite difficult. Which is to say it is absolutely essential that we work HARD to have conversations where we WORK THE PROBLEM.

To do that effectively, we have to make sure that everyone get's heard.

To that point:

If you're like me and you can't wait to get your ideas out there... please take a breath and wait. That is to say please make a double extra effort to dial yourself back a bit and LISTEN to your groupies.

If you're sometimes uncomfortable talking in your group and you are perfectly comfortable letting other folks talk, please make a a double-extra effort to SPEAK up.

If you are somewhere in between, then you have a golden opportunity to help by

Asking leading questions:

"What do you think about...."

"Why do you suppose that..."

"I'm not so sure about the < >, what do you think?"

Try to avoid 'convincing' a groupmate that they are wrong.

Try to avoid 'convincing' a groupmate that you are right.

Encourage your groupmates to share their thoughts.

Speak up when an idea comes to mind.

Take your time, relax, be Gracious

Be humble

Seriously

BACKGROUND:

  • The Pacific Northwest is prone to extremely violent earthquakes that occur every 300 - 500 years.
  • Those subduction zone earthquakes are expected to have catestrophic effects much the same as the Indonesia quake in 2004 and the Japan quake in 2011.

GOAL:

To successfully model ground motion and associated damage to structures in Gig Harbor during a full rip of the CSZ (magnitude 9.0) in our classroom using a 'shake table'.

BACKGROUND INFO:

In order to 'successfully' model a 9.0 CSZ event, you have to know what to expect in GH during such an earthquake. A great deal of very helpful information can be found here:

  • Reading 1: Cascadia Subduction Zone Earthquakes: A magnitude 9.0 Scenario
  • Reading 2: Using the CREW Scenario: Three Tabletop Exercises
  • Reading 3: Understanding Earthquake Hazards in Washington State:
    Modeling a Magnitude 9.0 Earthquake on the Cascadia Subduction Zone off the Pacific Coast

1) You have to form a well grounded (pardon the pun!) understanding of ground motion at various places along the CSZ and especially in Gig Harbor.

2) You have to develop a scale system to fit your desktop 'shake table'. This is very, very difficult. The goal is NOT to develop structures that survive a 9.0 CSZ event. Your job is to design and build structures that accurately mimic structures in Gig Harbor. Some of those will fail and some will not.

Please include include models for:

1) Hosipitals

2) Homes

3) Water/sewage pipes

4) Electrical transmission lines

5) Roads

6) Bridges.

 

 

BACKGROUND INVESTIGATION:

  • Determine some sort of a scale for your buildings so that you can appropriately size them on your shake table. This is absolutely critical and VERY, very difficult. For example, a house might be built using wooden beams measuing 4" x 8" and supports made of 4" x 4" ("Four-by-Fours") and walls held up by 2" x 4" ("Two-by-Fours"). Our lab 'shake tables" won't support any of those. We will be using much lighter materials.
  • Use the Lab Quest with the attached accelerometers to get an actual "feel" for PGA (Peak Ground Accelerations) that we can expect in Gig Harbor.
  • Determine an appropriate acceleration to model shaking in your model (this is key)
  • Determine how you will *accurately* reproduce that amount of ground motion for each trial
  • Determine an appropriate time for your model to experience the ground motio

PRE-LAB DESIGN DISCUSSIONS:

Determine how you will construct your models--

Available materials:

  • Cardboard to lay over the wood (allows for piercing, punturing, gluing etc...)
  • Something to model transmission lines
  • Something to model water/sewer lines)
  • Something to model hospitals and other high tolerance buildings
  • Anything you'd like to bring from home
  • glue, tape, string

LAB:

  • Build your model
  • Produce ground motions at appropriate 'g' strength
  • observe results
  • Revise your models
  • Repeat
  • Revise as needed

LAB REPORT:

  • Investigative Question/Purpose:

    How accurately can we model the effects in Gig Harbor of a 9.0 CSZ event using a classroom shake-table.

    The purpose of this lab is NOT to try and make a model for a large quake in our area. The goal is to see HOW WELL you can accurately model the effects of such a quake on Gig Habor. Some model objects should fail, some should survive and some should be somewhere inbetween.

  • The most important section of your lab report is the 'methods' section. The score in this section doubles from 2 pts to 4 pts and I'll be looking to see how well you document the conversations and changes you made to your modeling. There should be many revisions, tests and remodeling and retesting done. Please make sure all of those are well documented.
  • This is a very difficult model to construct. There are an additional 2 pts available for a successful model. That means all model objects that are modelled to fail will do so. All model objects designed to survive will do so.