Some earthquake software

While I was preparing the last entry, I came across some software available through the USGS web pages.

Note that FORTRAN lives!

These are:

1. 3D Focal Mechanisms - a tool for viewing earthquake focal mechanism symbols three dimensionally
2. 3D velocity modeling
3. Cleanstrain - a program to process strainmeter data.
4. CLUSTER2000 - recognizes clusters in space-time in an earthquake catalog
5. Coulomb 3 - designed to investigate Coulomb stress changes on mapped faults and earthquake nodal planes
6. FPFIT - a Fortran program that computes double-couple fault plane solutions from P-wave first motion data
7. Ground Motion Parameter Calculator
8. HASH - a Fortran 77 code that computes double-couple earthquake focal mechanisms from P-wave first motion polarity observations
9. HypoDD - a Fortran computer program package for relocating earthquakes with the double-difference (DD) algorithm
10. HYPOINVERSE2000 - determines earthquake locations and magnitudes from seismic network data like first-arrival P and S arrival times, amplitudes and coda durations
11. MacR1D - a one-dimensional seismic travel-time calculator for Macintosh
12. MacRay - a general purpose two-dimensional seismic ray-tracer for Macintosh
13. OpenSHA - an effort to develop object-oriented, web- & GUI-enabled, open-source, and freely available code for conducting Seismic Hazard Analyses
14. PQLX - open-source software system for evaluating seismic station performance and data quality
15. Probabilistic Seismic Hazard Calculation Software
16. Quake Data Distribution System (QDDS) - provides a method for distributing earthquake data over the Internet in near-real time
17. The Quake Data Merge Real Time Merged Catalog (QDM) software
18. SATSI (Spatial And Temporal Stress Inversion) - inverts focal mechanism data for a spatially and/or temporally varying stress field
19. ShakeCast - delivers maps of areas affected by an earthquake
20. Slick Package - uses fault slip data (either field observations or from focal mechanism) to find the stress tensor that best explains the observations
21. Slope Performance During an Earthquake

Seismograph widget for your Macintosh

A while back, I wrote about the Macintosh program Seismac that would use the sudden motion sensor in your computer (you know, in case you knock your Mac off the table, to stop the hard drive) to display a 3-axis accelerogram. It is a great teaching aid.

My IT colleague Teb not only relieved me of some candy this weekend (with his kids), but he told me that this capability is now available for Macs as a "widget" (a little snippet of software).

You can download it from Apple. Free, only 141k. 
System requirements - Mac OS X 10.4 or later; Macbook, Powerbook or iBook

Turn your laptop into a seismograph

"Inside your laptop is a small accelerometer chip, there to protect the delicate moving parts of your hard disk from sudden jolts.

"It turns out that the same chip is a pretty good earthquake sensor, too—especially if the signals from lots of them are compared, in order to filter out more mundane sources of laptop vibrations, such as typing.

"It's an approach that is starting to gain acceptance. The project Quake Catcher Network (QCN), already has about 1500 laptops connected in a network that has detected several tremors, including a magnitude 5.4 quake in Los Angeles in July. Led by Elizabeth Cochran at the University of California, Riverside, and Jesse Lawrence at Stanford University, QCN uses the same BOINC platform for volunteer computing that projects like SETI@home rely on.

"One of the benefits of this new technology is price: Research-grade earthquake sensors typically cost between $10,000 and $100,000. Of course, they are much more sensitive, and can detect the subtle signals of far-away quakes that laptops will never pick up. But Lawrence notes that, 'with many more cheap sensors, instead of guessing where strong motions were felt by interpolating between sensors, we should be able to know where strong motions were felt immediately, because we have sensors there.'

"Another advantage is that QCN sensors can record the maximum ground shaking. Many high-sensitivity sensors cut short the full extent of the oscillations they are measuring even for moderate earthquakes. Lawrence argues that with enough sensors, eventually 'we should have the ability to triangulate earthquakes for earthquake early warning, providing several seconds of warning before the earthquake hits neighboring populated regions.'

"There is a catch with the QCN sensors, though: getting accurate coordinates for their position. At present, since most laptops do not have GPS, the project relies on coordinates that the users type in. Fortunately, rough coordinates can also be automatically retrieved from network routers that the laptop is connected to, as a backup.

It all started with teenage mutant ninjas

"Laptop accelerometers were never meant to be used this way. But in 2005, a benign hacker group called the teenage mutant ninjas figured out how to access the 'sudden motion sensor' in Apple computers. A year later, David Griscom at the company Suitable Systems wrote SeisMac as an educational tool for IRIS, a group of U.S. earthquake seismologists.

"Cochran had the idea that this approach could be linked with BOINC. Carl Christensen, a distributed computing expert, was recruited to implement QCN in BOINC last year. A first limited release was made in March of this year, and by April the network had already detected its first quake, in Reno, Nevada.

"Christensen is now working on integrating stand-alone sensors that attach to desktop machines with USB connections (since desktops don't get bumped around like laptops, they don't have built-in sensors). These USB sensors can be as cheap as $30, and the idea is to have large numbers of them sponsored as educational tools for schools.

"Lawrence notes that "the USB accelerometers will provide a stable backbone, without which the ever-changing configuration of laptops would not be quite as reliable. The USB accelerometers can also mount directly to the floor, which means they will have better sensitivity to ground motions." From AAAS.

Download Seismac for your Mac.

Join the Quake-Catcher Network.