Seismology with smart phones and Raspberry Shake geophone systems
Summary
This activity introduces students to the concept of vibration recording and the monitoring of seismic shaking. The basic concept is to use motion-sensing devices to understand the character of vibrations and distant seismic events. We use the three-component motion sensors (accelerometers) inside a smartphone as well as a vertical geophone and recording system called the Raspberry Shake to make the measurements. This activity develops some familiarity with software and communication systems as well as seismometry. It provides background for earthquake seismology, geotechnical engineering, and seismic exploration.
This activity was developed so that students can conduct seismic studies themselves with affordable equipment, when the in-person field course could not be held.
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Context
Audience
![[creative commons]](/images/creativecommons_16.png)
Skills and concepts that students must have mastered
It is best if students have an Introduction to Geophysics undergraduate course at the junior level as a prerequisite.
How the activity is situated in the course
This activity is one of several in the field course. The Raspberry Shake instrument should be installed toward the beginning of the course so that a range of events can be recorded over a period of days or weeks. The recorded results can then be analyzed and presented toward the end of the course.
Activity Length
We have an introductory lecture (30 minutes) on seismology then the students need about two hours of study to understand the Raspberry Shake and smartphone sensors. The Shake should be left monitoring for some days or weeks and reviewed regularly. The smartphone application can be undertaken in several hours. It should take several more hours to work up some of the results from the Raspberry Shake.
Goals
Content/concepts goals for this activity
Students will be able to:
- Analyze the seismic recordings using frequency spectra, amplitudes, and directions
- Analyze errors and uncertainties in the data
- Describe the basic methods of elastic-wave generation, propagation, and recording
- Collect measurements and recordings from two types of seismometers
- Explain data flow for a Raspberry Shake
Higher order thinking skills goals for this activity
- Design a small seismic experiment, collect data from two instruments, and analyze the results
- Calculate the distance to the epicenter of a seismic event (made with a hammer)
Other skills goals for this activity
- Be able to use smartphone motion detector and Raspberry Shake seismometer
Description and Teaching Materials
Getting started
Orient the students to the purpose and applications for seismic studies. Sonar surveys can be used to inform applications such as boating, construction, fishing, dredging, archaeology, stratigraphy, or coastal evolution.
- Presentation: Introduction to Seismology Activity (Acrobat (PDF) 3.9MB Oct29 20)
Activity
The Raspberry Shake unit in this activity is best placed in a location with good coupling to the Earth (basement or protected outdoors position). Power and an internet connection are required for the Raspberry Shake. Smartphone apps that can be used include those by ExaMobileSA (Vibration Meter), Seismometer 6, Vibsensor, and Twiddlefactor (MC Sensors). They have associated documentation.
- Seismology Activity and Instructions (Microsoft Word 2007 (.docx) 817kB Oct29 20)
- Setting Up Your Raspberry Shake (Acrobat (PDF) 629kB Oct29 20)
Technology Needs
- Smart phone with accelerometer app
- Raspberry Shake seismometer
Teaching Notes and Tips
- Introduce the Raspberry Shake instrument early in the course to allow multiple days of recording and the possibility of detecting interesting events.
- Encourage regular review of the continuous recordings
Assessment
The activity can be evaluated by documentation with plots, pictures, video, report, and digital data. The quality of the description of the recorded events and the sophistication of their analysis can be the basis for evaluation.