Admin Table of Contents
What do Tiltmeters and creep meters measure?
A tiltmeter measures tilting or raising of the ground in vertical movement. Creep meters measure horizontal movement by using a wire stretched across a fault.
What is a fault creep?
Fault creep is a behavior of some faults where the two sides of a fault slowly slide past one another in the absence of large earthquakes. This is a form of aseismic slip and can be continuous or episodic.
What are 4 instruments used to detect movement along faults?
Four instruments that are used to monitor faults are creep meters, laser-ranging devices, tiltmeters, and satellites. A creep meter uses a wire stretched across a fault to measure sideways movement of the ground. A laser-ranging device uses a laser beam bounced off a reflector to detect even slight fault movements.
What do creep meters measure?
Creepmeters. A creepmeter measures fault slip by recording the displacement between 2 piers or monuments located on opposite sides of the fault, spaced 30 meters apart. Its displacement relative to the second pier is measured electronically and checked periodically with a mechanical measurement.
What does a tiltmeter measure?
Tiltmeters continuously measure the tilt of the ground surface. Like a carpenter’s level, an electronic tiltmeter uses a small container filled with a conducting fluid and a “bubble” to measure a change in slope. Tilt is measured in microradians, which is a small fraction of a degree.
What is a creep meter used for?
A Creep Meter uses a wire stretched across a fault to measure horizontal movement of the ground. Home Science Math and Arithmetic History Literature and Language
What factors affect the creep of a creepmeter?
Because the piers are anchored to about 2 meters depth, they are subject to the influence of seasonal (winter) rainfall. Many of the creepmeters show an annual cycle due to the wetting and drying of the near-surface materials within the fault zone. In addition, creep is influenced by large rainfall events and nearby earthquakes.
Where are the instruments being used to measure earthquakes?
Currently, numerous instruments have been installed by the USGS along the San Andreas fault, in the Long Valley Caldera, and by other institutions near active faults and volcanoes in the US, Japan, China, Iceland, Italy, and Taiwan.
How is an invar wire stretched across a fault?
Typically, an invar wire (or a graphic rod) is anchored to one pier and is stretched across the fault. Its displacement relative to the second pier is measured electronically and checked periodically with a mechanical measurement.