Geophysical Instruments

Geophysical instruments measure the physical attributes of the Earth, and these measurements are collected for use by the UNAVCO science community.

GNSS/GPS

GNSS/GPS Receivers (GPS, GLONASS, etc) collect GNSS data which, after processing, is used to measure millimeter-level surface motion measurements at specific points over a period of time; the datasets include temporary, episodic campaign surveys and permanent installations.

Geodetic Imaging

Geodetic Imaging uses data from radar or optical laser which, after processing, is used to measure centimeter-scale motions on the Earth's surface over several square meters to hundreds of square kilometers.

• SAR Satellites — synthetic apeture radar from sun-synchronous polar orbiting satellites in the L-, C-, and X-bands.
• Terrestrial Laser Scanning (TLS) — land-based LiDAR.

Laser Strainmeters

Laser Strainmeters are long-baseline (on the order of 0.5 km) measurements of deformation on the Earth's surface.

Borehole Instrumentation

Borehole instrumentation is grouted in place 100 to 250 m below the surface to operate at the low noise levels required to capture small, short term transients. The instrumentation in the borehole casing can include:

• Borehole Strainmeters — to measure, after processing, crustal deformation on a timescale of less than a second to weeks or months.
• Borehole Seismometers — to detect seismic waves at periods of several minutes or less.
• Borehole Pore Pressure Sensors — designed to measure fluctuations in groundwater pressure to help characterize the hydrological response of sites at time scales of seconds to years.
• Borehole Tiltmeters — to measure tilt from crustal deformation due to deep earth processes such as volcanism and water table recharge/discharge over periods of seconds to weeks.

Meteorological

Meteorological Systems can be co-located with other geodetic instruments to provide near-surface atmospheric measurements.

Tide Gauge

Tide Gauge Systems can be co-located with other geodetic instruments to provide sea level measurements.