Plotting earthquakes on a map

Lecture

• Time: 9:00 am - 12:pm, Tuesday, 11/26 (You can come around 10 am if you know how to finish Tasks 0 and 1)
• Location: NS 206 (department conference room)

Goals

• Plot topography maps using GMT5 (The latest stable version GMT6 is available online, you can try to finish all the tasks using GMT6, but I cannot guarantee I can help.)
• Plot earthquakes on a map
• Plot focal mechanisms of earthquakes on a map

GMT

GMT (The Generic Mapping Tools) is the most commonly used software in the geophysics community for plotting high-quality figures, especially maps. Dr. Dongdong Tian is an expert and one of the core developers.

• GMT5 installation: http://gmt.soest.hawaii.edu/?id=Installing
• GMT5 official documentation: http://gmt.soest.hawaii.edu/doc/5.4.5/index.html
• GMT5 examples: https://docs.generic-mapping-tools.org/5.4/Gallery.html#the-50-examples
• GMT new home: https://www.generic-mapping-tools.org
• How to cite: https://www.generic-mapping-tools.org/cite/ (MSU Geological Sciences Endowment partially supports the development!)

ISC catalog

ISC (International Seismological Centre) catalog is usually considered to be the final catalog of global earthquake data. It contains data from 1900 to now. In ISC catalog, earthquake information are automatically determined, and then manually inspected by ISC analysts and relocated if possible. The manually reviewed ISC catalog is typically 24 months behind real-time. Currently (in 2019), only the earthquake information from 1900 to 2016 are manually reviewed.

• Homepage: http://www.isc.ac.uk/iscbulletin/
• Search: http://www.isc.ac.uk/iscbulletin/search/catalogue/
• How to cite: http://www.isc.ac.uk/iscbulletin/citing.php

Global CMT Project

The Global Centroid-Moment-Tensor (CMT) Project provides focal mechanisms of global earthquakes with magnitudes larger than 5.

• Homepage: https://www.globalcmt.org
• Search: https://www.globalcmt.org/CMTsearch.html
• How to cite: https://www.globalcmt.org/CMTcite.html

Task 0: preparation

1. Download the necessary materials: (beachball.zip)
2. Download and install GMT on your own laptop (Please install GMT 5.4.5 for the lecture. Standalone installer for Mac unless you are an expert on bash)

Task 1: plot a topography map for the GLG 401 field trip

1. Read file 'plotmap401.gmt5' using a text editor. (Note the filename extension means nothing)
2. Run 'bash ./plotmap401.gmt5', check the output file 'mapGLG401.pdf'.
3. Can you find Houghton, Munising, and Picture Rocks on the map?

Task 2: plot a topography map of Michigan

1. Read file 'plotmapMI.gmt5' using a text editor. (Note the filename extension means nothing)
2. Run 'bash ./plotmapMI.gmt5', check the output file 'mapMI.pdf'.
3. Change variables 'outf', 'area', 'proj' in file 'plotmapMI.gmt5' for another region. (Note the projection parameters 'proj' should be consistent with the region parameters 'area'. Recommended values are (longtidue of the map center)/(latitude of the map center)/(minimum latitude)/(maximum latitude)/(map width). A map width of '5c' means 5 centimeter, and '5i' means 5 inches.)

Task 3: plot earthquake epicenters on a map of Michigan

1. Search earthquake catalog from the ISC website: http://www.isc.ac.uk/iscbulletin/search/catalogue/
   • Database: Reviewed ISC Bulletin
   • Output format: CSV formatted
   • Rectangular search: bottom latitude: 40, top latitude: 50, left longitude: -90, right longitude: -80 (you can also try other regions)
   • Time period: start date: 2010/01/01 00:00:00, end data: 2016/01/01 00:00:00
   • No change for 'Additional search parameters'
   • Output links in the outputs: No (check the box out)
   • Click the bottom button 'Output event catalogue'. (It may take a while to create a list)
   • You will get a catalog from a new window. Copy and paste the catalog to a local file called 'ISC_MI.lst' (Note please skip the header lines, start from the first earthquake, and end at the last earthquake.)
2. Run 'bash ./plotmapEQMI.gmt5', check the output file 'mapEQMI.pdf'.
3. Search for earthquakes in another region, download the catalog, and plot a map. You also need to change variables 'outf', 'area', 'proj' in file 'plotmapEQMI.gmt5' for the new region.
4. Compare files 'plotmapMI.gmt5' and 'plotmapEQMI.gmt5'. What is the difference?

Task 4: plot earthquake epicenters and focal mechanisms on a map of California

1. Search earthquake catalog from the ISC website: http://www.isc.ac.uk/iscbulletin/search/catalogue/
   • Database: Reviewed ISC Bulletin
   • Output format: CSV formatted
   • Rectangular search: bottom latitude: 32, top latitude: 43, left longitude: -125, right longitude: -114
   • Time period: start date: 2010/01/01 00:00:00, end data: 2011/01/01 00:00:00 (one year is more than enough!)
   • No change for 'Additional search parameters'
   • Output links in the outputs: No (check the box out)
   • Click the bottom button 'Output event catalogue'. (It may take a while to create a list)
   • You will get a catalog in a new window. Copy and paste the catalog to a local file called 'ISC_CA.lst' (Please skip the header lines, start from the first earthquake, and end at the last earthquake.)
2. Search the global CMT solutions from https://www.globalcmt.org/CMTsearch.html
   • Date constraints: starting data: 2010/01/01, end data: 2011/01/01
   • Location constraints: latitude from 32 to 43, longitude from -125 to -114
   • Output type: 'GMT psmeca input'
   • Keep the other default parameters
   • Click the bottom button 'Done'.
   • You will get a list in the same window. Copy and paste the list to a local file called 'CMT_CA.lst' (Please skip the header lines, start from the first earthquake, and end at the last earthquake. Note here are only 6 parameters to represent the moment tensro: mrr mtt mpp mrt mrp mtp)
3. Run 'bash ./plotmapCMTCA.gmt5', check the output file 'mapCMTCA.pdf'.
4. In 'plotmapCMTCA.gmt5', in the line of 'psmeca', try to replace '-Sm0.5' with '-Sd0.5', check the new output file. What is the difference?
5. Search for earthquakes during another time period, download the catalog, and plot a map.
6. Compare files 'plotmapEQMI.gmt5' and 'plotmapCMTCA.gmt5'. What is the difference?