Instrument Noise Reduction
Seismic instrumentation is sensitive to a number of non-seismic sources such as wind-induced tilt, temperature changes, and variations in Earth's magnetic field. To help isolate instruments from such noise sources, the USGS conducts experiments on installation techniques, including testing different vault designs, assessing different materials for thermal properties, and evaluating enclosures for magnetic shielding.
Most modern seismometers use an analog electronic feedback system, which must be digitized and then converted from units of volts to displacement. These systems must be calibrated routinely in order to verify the response of the system. Scientists are currently working on new ways to calibrate these instruments, including shake table testing and injecting known voltages into the instrument. By analyzing these signals, scientists are able to characterize the instruments to a high precision.
Identification of potential data quality problems
Scientists are also investigating potential problems with instrumentation by examining data quality. This includes using earthquakes, co-locating instruments as well as comparing long-term trends in noise levels at stations. By using such signals, scientists can identify anomalous behavior, which could be compromising the quality of data produced at a seismic station.
Detecting and accurately locating seismic events and slower crustal movements depends on sensitive instruments and good models (equations that describe characteristics of the earth’s structure). Scientists are performing research to improve several aspects of monitoring:
- Changes to allow NEIC to trigger on smaller earthquakes.
- Evaluation of alternate method of locating earthquakes.
- Improving earthquake early warning and rapid response using real time high rate GPS data.
- Enable objective, automated geodetic data monitoring and rapid deformation event analysis.