The PBO is a network of deformation sensors (GPS and strainmeters) for the western United States similar to that deployed at Parkfield. USArray consists of a large transportable broadband seismic array, augmented by smaller seismic arrays and coordinated with the USGS Advanced National Seismic System ( ANSS). The other elements of EarthScope include USArray, and the Plate Boundary Observatory (PBO). SAFOD is funded by NSF as part of an ambitious scientific initiative called EarthScope. PBO is a geodetic observatory designed to study the three-dimensional strain field resulting from plate boundary deformation. By observing quakes "up close," SAFOD will mark a major advance in the pursuit of a rigorous scientific basis for assessing earthquake hazards and predicting earthquakes. SAFOD will provide direct information on the composition and mechanical properties of rocks in the fault zone, the nature of stresses responsible for earthquakes, the role of fluids in controlling faulting and earthquake recurrence, and the physics of earthquake initiation and rupture. SAFOD's long-term monitoring activities will include detailed seismological observations of small to moderate earthquakes and continuous measurements of rock deformation and other parameters during the earthquake cycle. Fault-zone rocks and fluids will be retrieved for laboratory analyses, and geophysical measurments will be made within the active fault zone.
This project will directly reveal, for the first time, the physical and chemical processes controllingĮarthquake generation within a seismically active fault.ĭrilling the hole for SAFOD starts west of the San Andreas Fault and then use advanced directional-drilling technology developed by the petroleum industry to angle the hole through the entire fault zone until relatively undisturbed rock is reached on the east side. These instruments, set 2 to 3 km beneath the Earth's surface, will form a San Andreas Fault Observatory at Depth (SAFOD).
#WHERE IS THE SAN ANDREAS FAULT INSTALL#
The colors in the subsurface show electrical resistivity of the rocks as determined from surface surveys the lowest-resistivity rocks (red) above the area of minor earthquakes may represent a fluid-rich zone.īuilding on more than 15 years of experience from the Parkfield Earthquake Experiment, the National Science Foundation (NSF) and the USGS started in June 2004 to drill a deep hole in order to install instruments directly within the San Andreas Fault Zone near the initiation point of previous magnitude 6 Parkfield earthquakes ( drill hole location in relation to slip rate). White dots represent area of persistent minor seismicity at depths of 2.5 to more than 10 km. Red dots in drill holes show sites of monitoring instruments. Schematic cross section of the San Andreas Fault Zone at Parkfield, showing the drill hole for the San Andreas Fault Observatory at Depth (SAFOD) and the pilot hole drilled in 2002.
0 kommentar(er)
