What Is a Seismometer?
A seismometer, a type of seismograph, is an instrument that converts the movements caused by earthquakes into electrical signals. It measures, calculates, displays, and transmits seismic intensity as numerical information. These devices are essential for objective observation and quantification of seismic activity.
The Japan Meteorological Agency (JMA) uses a seismic intensity scale from 0 to 7 to measure and publicize earthquake intensities. Seismometers must pass regular inspections to ensure the accuracy of observations.
Modern seismometers can calculate seismic intensity in real-time, with some models providing measurements every minute or even faster, at 1/100th of a second.
Uses of Seismometers
Seismometers are used for detecting earthquakes and providing crucial information for evacuation advisories. They help in:
- Shutting down equipment based on seismic intensity to prevent further damage
- Broadcasting bulletins during earthquakes
- Estimating damage to buildings and populations based on seismic intensity distribution
- Initiating disaster countermeasures based on the scale of damage
In addition, seismometers are increasingly used in factories and large commercial facilities for rapid evacuation and disaster prevention.
Principles of Seismometers
Seismometers consist of a measurement section, typically an accelerometer, and a calculation section. The accelerometer converts shaking into electrical signals, which are then calculated into seismic intensity by the device’s processing part, following algorithms specified by the JMA.
These instruments can display various earthquake data and store this information in built-in memory or other storage media for later analysis.
Seismometer Apps
Smartphone and tablet apps have been developed to utilize built-in acceleration sensors for measuring seismic activity. Some apps can even transmit preliminary tremor data to the cloud for early earthquake warnings.
Environmental Standards for Installation of Seismometers
Installation of seismometers follows strict environmental standards to ensure accurate data collection. This includes considerations for location, such as avoiding cliffs or uneven terrain, and specific requirements for the seismometer stand, like material and construction, to ensure stability during strong earthquakes.