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

  • Well Log

    Well Log (Boring Log) Well Log: A geological well log (or boring log) is a detailed record of subsurface materials encountered during a drilling project. Boring logs, or well logs, are written by a geologist, and describe the physical subsurface characteristics and lithological units encountered during well-plotting. Well logs include information about depth, different formations,…

  • Mineral

    Mineral Definition A mineral is defined as an inorganic element, compound, or substance that naturally develops with an organized internal structure and/or crystal form over time. Minerals are also distinguishable by their chemical composition and physical properties, as determined in laboratories by geologists. Typical earth minerals found in most igneous, metamorphic, and sedimentary rocks are…

  • De-watering System

    De-Watering System in Methane Mitigation De-Watering: In accordance with the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, a de-watering system is a permanent water removal system in a methane mitigation system. In the mitigation process, a de-watering system consists of perforated horizontal pipes, gravel pockets, sump areas with pumps,…

  • Reverse Fault Definition

    Reverse Fault Reverse Fault: In the field of geology, a reverse fault is a dip-slip fault in which the hanging wall moves upwards, relative to the footwall. The average dipping angle of a reverse fault ranges from 45 to 90 degrees. However, if less than 45 degrees, it becomes a “thrust fault.” Reverse faults are…

  • Confined Aquifer

    Confined Aquifer Confined Aquifer: In the hydrogeology branch of geology, a confined aquifer is an aquifer that is overlain (and underlain) by a layer of low permeability, such as clay, shale, or silty clay. In fact, the two confining layers contain the storage and flow of groundwater, such that the aquifer maintains hydraulic pressure (or…