Crustal Deformation Data The US Geological Survey maintains a
variety of fault and volcano monitoring sites around the western
United States. Instruments at these sites include strainmeters,
tiltmeters, magnetometers, creepmeters, pore pressure monitors,
as well as other environmental parameters such as temperature
and barometric pressure. The data are collected and monitored to
help understand how, when, and why large earthquakes, fault slip
and volcanic activity occur. The measurements provide a near
real-time record of the related crustal deformation before,
during and after events. The goal is to better understand these
natural processes, and use these data to reduce the earthquake
and volcanic hazards associated with them. This web site
provides data plots and data downloads for many instruments that
are concentrated in areas where large earthquakes are likely to
occur in California and areas of known volcanic activity (Long
Valley, CA). In particular, the USGS has concentrated
instrumentation efforts in