Alquist-Priolo Earthquake Fault Zoning Act

Alquist-Priolo Earthquake Fault Zoning Act

Alquist-Priolo Earthquake Fault Zoning Act: The Alquist-Priolo Earthquake Fault Zoning Act is a law that assists geologists to define “active faults” versus “potentially active faults.” The process entails using the same aging criteria as the United States Geological Survey (USGS) and the California Geological Survey (CGS). In fact, California policy requires zoning any potentially active fault that possesses a relatively high potential for ground rupture, for future public reference. The law was originally passed in 1972 as the “Alquist-Priolo Special Studies Zones Act.” Currently, it has undergone some reform, and is now referred to as the “Alquist-Priolo Earthquake Fault Zoning Act.”

The Alquist-Priolo Earthquake Fault Zoning Act commonly applies to the seismology, engineering geology, and geotechnical branches of geology.

Fault Investigations

As per the CGS, strike-slip faults and dip-slip faults may be categorized as “active,” “potentially active,” or “inactive.” Active faults show displacement within the past 11,000 years. Potentially active faults show displacement within the last 1.6 million years. And inactive faults show no evidence of displacement within the last 1.6 million years.

Similar Posts

  • Troposphere

    Troposphere Troposphere: The troposphere of a terrestrial planet is the lowest member of the atmosphere. On Earth, the troposphere starts atop the ground surface and terminates roughly 10 kilometers above mean sea level. In fact, geologists understand that most of the Earth’s water vapor (clouds) exists in the troposphere. And the next member of the…

  • Unconfined Aquifer

    Unconfined Aquifer Unconfined Aquifer: In the hydrogeology branch of geology, an unconfined aquifer is an aquifer that has a water table. In fact, an unconfined aquifer can only be the uppermost hydrogeologic unit and is particularly one that has no hydraulic head (or pressure) that is equal to atmospheric pressure. To illustrate, depth to groundwater…

  • Unobstructed Opening in Methane Mitigation

    Unobstructed Opening Definition in Methane Mitigation Unobstructed Opening: Per the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, an unobstructed opening is a permanent clearance or gap in the walls, floors, or ceiling of a structure, to allow for direct fresh airflow. In methane mitigation plan applications, this does not…

  • Fault Creep

    Fault Creep Fault Creep: Fault creep means slow ground displacement of a strike-slip fault or dip-slip fault, that usually occurs without accompanying earthquakes. Fault creep can derive from tectonic activity, or be the result of excessive petroleum and groundwater pumping.