WWU Seismograph on the WWW

Welcome to the Seismograph on the WWW site at Western Washington University.  First and foremost, you should know that the central pillar of this site is a Java(TM) applet.  So, in order to fully appreciate this site in all of its grandeur, it is necessary to have a Java-capable web browser.

NEWS!!!

Table of Contents

• The Seismolet
• What
• Why
• How
• Who
• Future

What

    The seismograph applet is a Java applet that displays real-time data obtained from a real, live seismometer located at Western Washington University, in Bellingham, Washington.  This means that if you so chose, you could spend hours upon hours sitting and staring at the seismograph, waiting so that you could call you're friends up and say,

"Hey, <name>, wakeup!  What?  Yes, I know that it's 3:00 in the morning.  But guess what?  There's an earthquake happening somewhere around Bellingham, Washington!  'Cause I can see it!  It's on the Web!  Yeah, because I've got the Internet in my computer!"
 
    The seismograph updates once every second, and has a data point for every 1/2 second.  It displays the output voltage of the seismometer, pictured above, in millivolts.  The range is adjustable, so that users can magnify the everyday background-noise to make their lives more exciting, or be more realistic, and watch a nearly straight line.  If you are wondering how an applet can read a seismometer, see How.

Why

    The Seismograph Applet has several possible uses, one of which is demonstrated above.  In addition, it:
 
1. demonstrates that Bellingham isn't a completely quiet town.
2. shows that Java has at least one use other that scolling text in fourteen different colors.
3. will enable Aaron to finally graduate from WWU. (See Who.)
4. allows an incredibly lucky visitor to witness actual seismic activity, complete with P, S, and Rayleigh-waves!
 
    Other uses may be invented in the future.

How

    Although the seismometer applet is the only part of the operation that you, the end-user, ever witnesses firsthand, the applet is just the tip of the proverbial iceberg.  Lying beneath the sea of the Web, connected to the applet by only a thin TCP hose, are the guts of the whole system.  The distinct organs present in the operation are:
 
1. The Seismometer - Model S102 from Engineering Acoustics Incorporated
2. The A/D Board - CIO-DAS08Jr/16 from ComputerBoards, Inc.
3. The Computer and Operating System - Benioff, a 450MHz Intel Pentium III with 400+ MB RAM, and a 1GB HD running NetBSD 1.3
4. The Device Driver - Written in C and compiled into a custom NetBSD kernel.
5. The Data Acquisition Program - Also written in C.  Transfers data to a shared-memory array.
6. The Web Server - The one. The only. Apache.
7. The Data Serving Daemon - Yes, it's written in C too.  Spawns child processes which feed data to applets.
8. The Applet - Written in Java.  Graphs the data it receives from a Data Serving Daemon-child.

    There are basically 3 different simultaneous processes present in this system.
 

1. Data Acquisition
2. Data Serving and Display
3. Web Serving

    The seismometer, the A/D board, the device driver, and the data acquisition program are all involved in the data acquisition process.  When the seismometer detects a vertical displacement of the ground that it is sitting upon, it changes the voltage that it outputs, to reflect that displacement.  Meanwhile, the device driver, which resides in the kernel of NetBSD on Benioff, is causing the A/D board to capture the signal from the seismograph once every 1/10 of a second.  The data acquisition program reads from the device driver , also at ten times a second, and copies the data available into a buffer that exists in shared memory.  The buffer is in shared memory so that many programs can read from it at once.

    Web Serving is done by the freeware Apache web server.  It even served out the page you are now reading, however, the web server's most important function in this system is to serve the Java seismograph applet out to be run on a web browser, so that the rest of the system has something to do.

    Data serving and display involves the shared-memory buffer, the data serving daemon, and the seismograph applet.  When the seismograph applet gets executed by someone's web browser, it opens a TCP connection to the data serving daemon.  the daemon then spawn of a duplicate of itself that starts reading the shared-memory buffer and sends the data across the TCP connection to the applet as new data arrives in the buffer.  The seismograph applet uses the data it receives to display a graph of the changing output voltage of the seismometer, which the applet updates whenever the daemon spawn sends it new data.

    The net result of this system is a seismograph on the web.  Pretty cool, huh?

 

Who

    This project was undertaken by Aaron Burmester for the primary purpose of satisfying the WWU Honors Program's senior project requirement, and for the secondary purpose of playing around with computers.  Faculty advisement, and assistance with NetBSD were provided by Dr. Phil Nelson of the WWU Computer Science department.  Assistance with hardware, and geologic expertise were provided by Dr. Russ Burmester and Dr. Bernie Housen of the Geology department.
 

Future

Anticipated future improvements include:
 
1. Continuous recording of seismometer output for analysis at a later date. DONE!
2. Intelligent recognition and automated recording of significant seismic events.
3. Applet text labels that are always completely visible, regardless of host system.
4. Increased size of shared-memory array for full initialization of the applet graph. DONE!
5. Relocation of the seismometer to a quieter environment, allowing for detection of weaker seismic signals. DONE!