SSBW - IRIS DMC Tutorial 6: Fetch Scripts for Web Service Requests
In this interactive tutorial built for a learning management system, students 1) generate and interpret IRIS web service requests for metadata, earthquake information, and seismogram data using Fetch scripts from the Linux command line, 2) plot the magnitude of earthquakes over time using GMT to evaluate aftershock and swarm patterns of the 2020 Puerto Rico earthquake sequence, 3) select nearby seismic stations to request data from, 4) use SAC to visualize and interpret seismograms and potential errors (clipping).
The IRIS Seismology Skill Building Workshop (SSBW), which is a free, online, open-access, large-enrollment, 12-week summer workshop for upper level undergraduates.
Skills and concepts that students must have mastered
This assignment builds on prior experience using a Linux command line environment, IRIS web service requests, the SAC (Seismic Analysis Code) software, and an understanding of aftershock patterns, and what typical earthquake seismograms look like.
How the activity is situated in the course
This is assignment number 19 of 35 in the Seismology Skill Building Workshop (SSBW).
Content/concepts goals for this activity
Proficiency with IRIS Web Services, finding appropriate seismic stations, selecting appropriate program options, mainshocks, aftershocks, swarms, SAC, clipping.
Higher order thinking skills goals for this activity
Retrieving relevant information from digital sources to accomplish tasks, using correct programming syntax, evaluating and describing computing output in the context of science concepts.
Other skills goals for this activity
Description and Teaching Materials
1. Retrieve a catalog for the 2020 Magnitude 6.4 Puerto Rico earthquake sequence using the IRIS FetchEvent script
2. Plot the magnitude of earthquakes over time using GMT to review the swarm and aftershock patterns of this sequence
3. Retrieve a list of nearby stations in the PR network using the IRIS FetchMetadata script
4. Calculate the source-receiver distances using the GMT command mapproject
5. Retrieve a seismogram of the mainshock from the closest station using the IRIS FetchData script to demonstrate clipping
6. Convert data files from miniseed to SAC format and plot them with SAC
7. Retrieve seismograms of the mainshock from a range of stations using FetchData and use SAC to identify which are not clipped
Teaching Notes and Tips
This assignment was constructed in the Moodle learning management system, and has been exported in the GIFT format. More information about the syntax of this format can be found here: https://docs.moodle.org/en/GIFT_format
This assignment is automatically graded by the learning management system. The number of questions of each type used are:
12 multiple choice questions
11 multiple answer question
1 matching question
6 numeric questions (output values, quantifying output, plot measurement, calculation)
10 short answer (auto-graded) question
References and Resources
During the Seismology Skill Building Workshop, students are provided with a virtual Linux machine that was tailored to include the software specifically needed to complete the assignments. This software is all freely available on the internet, but interested parties are encouraged to contact the instructor for access to this tailored virtual machine.