Module 5 Summative Assessment
Instructions: In this assignment, you will compare the wave propagation models to empirical observations of the event. To do this you will use NCTR’s website and database from the tsunami on March 11, 2011 ( (link is external).
- To begin, select at least 3 sites with data from March 11, 2011 to possibly March 12, 2011. You will want them to align into a more-or-less straight transect moving from Japan toward the U.S. Remember the data you are working with are actual measurements taken from instruments either on land or at sea. You can select any site, but make sure they are spaced out relative to each other.
- For the buoy data sites once you click on a location on the website, you will use the Data Access section to select a start date of 2011, March, 11 and an end date of 2011, March 11 (or for March 12 if you are far away).
- For tide gauge data sites, you will be directed to NOAA Tides & Currents website that you are familiar with from Module 4.
- Once you have selected a site click on the Tides/Water Levels tab for the site. You will then need to scroll down and set the date From March 11 or 12th 2011.
- Units should be Meters, Timezone should be GMT, make sure you select 6 minute as your interval and then click Plot. Your chart will be generated at the top of the page.
- Once you bring up the data, you will be able to visually see the plots and as you hover the cursor over the data plot, each individual reading will be highlighted and you can read the exact values accordingly.
- Using your Worksheet, fill in the chart shown below with your observations and make the appropriate calculations. We have provided an example data entry for a buoy and for a land-based tide gauge station. Your entries should follow the same format as directed.
- Finish the assessment by answering the questions below the table, type up your data and submit a Microsoft Word document, complete with a neat orderly data table showing your readings and calculations.
Station # and Type / Approx. Latitude / Approx. Longitude / Water Depth (or predicted) / Approx. Date & Time of Wave / Water Column Height for Direct Wave (or verified water leve) / Tsunami Wave Height? Calculated Value
SSE Tokyo Japan / 30° 30’ N / 152° 7’ E / 5822 meters / 11:22 GMT
On 3/11/11 / 5825.3 meters / 5825.30 meters – 5822 meters =
9410170 (San Diego, CA Tide Gauge)
/ 32° 42’ N / 117°10’W / 1.341 meters / 07:30 GMT
On 3/12/11 / 1.929 meters / 1.929 meters – 1.341 meters = 0.588 meters
- Based on the details above, what have you learned about the evolution of the tsunami wave as it propagated by refraction and reflection across the Pacific Ocean?
- How long did it take for the wave to make the trip between your sites?
- Based on your data calculate the tsunami wave velocity (kilometers per hour?) for the direct wave. To calculate velocity, you need distance and time. Well you have time from the measurements above. To find distance:
- Note: You can easily use Google Earth’s measuring tool to measure the distance between your observation sites (use the Latitude & Longitude if needed). Once you have the separation distance between two of your sites, you can divide the distance in kilometers (numerator) by time between observations in hours. In our example in the table – the wave passed station 21413 at 11:22 a.m. on 3/11/11 and arrived at San Diego at 7:30 a.m. on 3/12/12. Thus the time between arrivals is just about 20 hours. Reasoning: 11:22 a.m. to 11:22 p.m. is 12 hours plus 11:22 p.m. to 7:22 a.m. is 8 hours for a total of about 20 hours – don’t worry about the 8 minutes as it is negligible for our purposes.
- Based on these observations and calculations, if you were a NCTR scientist responsible for issuing a warning after an earthquake occurs, how much time would it take to issue warnings and help get people to safety? What distance from the epicenter do you feel would essentially be a loss because of the inability to warn people appropriately within the bull’s eye region? This question is open-ended, as long as you provide details to support your point of view.