The Hawaiian Volcano Observatory celebrated the 30th anniversary of Mauna Loa's last eruption (in 1984) on March 25, 2014, underscoring that it has been a realtively quite 3 decades at the world's largest active volcano.
A tiltmeter, is a type of instrument used to detect any kind of tilt in the structure to which it is attached. Most tiltmeters use an air bubble in a liquid-filled tube, much like a typical carpenter's level, but are equipped with sensitive electronics that can detect even the tiniest change in tilt. They either sound an alarm or transmit the data to a remote monitor or other device.
A voltmeter is an instrument used for measuring electrical potential difference between two points in an electric circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage of the circuit; digital voltmeters give a numerical display of voltage by use of an analog to digital converter.Voltmeters are made in a wide range of styles.eneral purpose analog voltmeters may have an accuracy of a few percent of full scale, and are used with voltages from a fraction of a volt to several thousand volts. Digital meters can be made with high accuracy, typically better than 1%.