SO503 Honors Research Methods

Spring 2006

Time Series Analysis Lab

Insure that you do an update on your computer. The program we want is c:\guthprog\statist.exe.

Cinna Lomnitz and Sara Nilsen-Hofseth (EOS, 15 Feb 2005) discussed the record of the 2005 megathrust and earthquake in terms of the tide records at several stations, including Adak, AK and Crescent City, CA. They showed periodicity at frequencies of 0.3 to 0.5 milliHertz (0.0003 to 0.00005 Hertz), or periods of about 1 hour. The great earthquake took place on Sunday, December 26, 2004 at 00:58:53 (UTC).

• You can get observed tide data, recorded every 6 minutes, at http://co-ops.nos.noaa.gov/data_retrieve.shtml?input_code=111011111pwl
• You can get tidal predictions, also every 6 minutes, at http://co-ops.nos.noaa.gov/pred_retrieve.shtml?input_code=100001101ppr&type=pred

You will get the tide data for Crescent City CA, and  Point Reyes CA (to the south, 4 students). Get 6 days before the earthquake and 8 days afterwards.  There is a dBase file with the tides for these stations.  It has the predicted tide, the observed tide, and the difference between the two.

• What periods can you see in the tidal records, and which techniques best show them? Can you see the one hour period observed by Lomnitz and Nilsen-Hofseth?
• What is the lag in the tides from Crescent City to your other station? Which way is the tidal "wave" moving along the coast of North America? What technique lets you determine this?
• Can you remove the diurnal tide periods, and does that help your analysis for the earthquake records? Why do you think this is the case? 
• What can you see best in each of the three types of record?

Update MICRODEM.  Place these in the directory with MICRODEM, which is probably "c:\program files\petmar_trilobites\ microdem".  See the new item in the help file on Time Series Analysis, in the Contents Tab, in the "Step by step directions", on how to do time series analysis.

Update the help file for MICRODEM at http://www.usna.edu/Users/oceano/pguth/microdem/win32/microdem.chm

Update the executable for MICRODEM at http://www.usna.edu/Users/oceano/pguth/microdem/win32/microdem.exe   or http://www.usna.edu/Users/oceano/pguth/microdem/win32/microdem.zip  .  The zip version will have to unzipped, but will usually be more  current than the uncompressed version.

Get a dBase file with the tides for Crescent City, CA