HPWREN’s Role In the Development of a Prototype Seismometer

1. HPWREN’s Role In the Development of a Prototype Seismometer Jose Otero Mark Zumberge Jon Berger Erhard Wielandt HPWREN Users Meeting: Nov 3rd, 2006

2. Development of a Prototype Fiber Optical Seismometer Our ultimate goal is to create a borehole seismometer, which rivals or surpasses the STS-1 in terms of its noise floor at long periods and the STS-2 at short periods. • By removing electronics within the seismometer we can eliminate noise created by electrical components and eliminate thermal gradients created by self heating. • By removing electronics within the seismometer we are no longer vulnerable to environmental extremes and phenomena such as lightning! • HPWREN provides the real time networking and data transport necessary to make this possible. HPWREN Users Meeting: Nov 3rd, 2006

3. Leaf Spring Granite Pier Feedback Coil Michelson Interferometer Optical launcher Non-Flexing Base Plate 633 nm polarization maintaining fibers 633 nm multimode fibers Current SIFO Deployment at Piñon Flats Observatory, California With real-time HPWREN communication and networking one can instantly view the seismic signals being recorded by our prototype seismometer. We can also monitor environmental variables, make changes to the seismometer and power off the laser. HPWREN Users Meeting: Nov 3rd, 2006

4. The Michelson Interferometer (displacement detector) • The “Heart and Soul” of our seismometer lies in its novel approach to detecting motion on Earth’s surface. • SIFO, through the use of a Michelson Interferometer uses the physics of constructive and destructive interference of light to help detect small movements and earthquakes. • When the Earth’s surface moves, Scientists at Scripps Institution of Oceanography can be instantly notified. This is made possible by HPWREN’s real time network. HPWREN Users Meeting: Nov 3rd, 2006

5. 3-D Animation of SIFO in “Action” HPWREN Users Meeting: Nov 3rd, 2006 Video Credits: J. Otero, G. Smith, 2005

6. Comparison of the Fiber Optic Seismometer and STS-2 Local Event: Magnitude ~ 1.1 HPWREN Users Meeting: Nov 3rd, 2006

7. Comparison of the Fiber Optic Seismometer and STS-1 Regional Event: Magnitude ~ 6.1 Location: Acapulco, Mexico The HPWREN network allows us to look at earthquake data minutes after the event if needed. Because this seismometer is still a proto-type ,comparisons with well established seismometers, also on the HPWREN network, allow us to gauge how well our instrument is functioning. HPWREN Users Meeting: Nov 3rd, 2006

8. STS-2 Optical STS-1 Noise Comparison of the “Big-Three” • HPWREN is not only useful during earthquakes, however! In fact we often don’t want earthquakes! • When earthquakes are not occurring, we can study items such as earth tides and instrument noise. • The quieter the instrument, the better. To study Earth Noise lots of data and a reliable transport method to bring that data home are needed. HPWREN Users Meeting: Nov 3rd, 2006

9. The 8-Channel DSP and Real Time Monitoring • Data from the SIFO is collected via an 8-Channel 16 Bit Digital Signal Processor. This data is fed into a computer which streams data to UCSD via the HPWREN wireless network. • HPWREN also allows us to monitor environmental variables such as temperature and air pressure within the seismic vault. • With the HPWREN network simple tasks such as: rebooting the computer, making configuration changes to the seismometer, cycling DSP power, cycling laser power, collecting and storing data, and monitoring real time status of the seismometer are made possible! HPWREN Users Meeting: Nov 3rd, 2006

10. Special thanks to the staff of HPWREN for allowing us to reliably and efficiently conduct our research.