tiltmeter

Even in dams, they are slowly being replaced by the modern electronic tiltmeter.

A tiltmeter is an instrument designed to measure very small changes from the horizontal level, either on the ground or in structures.

The very first tiltmeter was a long-length stationary pendulum.

Volcano and earth-movement monitoring then used the water-tube, long baseline tiltmeter.

He has also directed and co-produced music videos for the bands Tiltmeter, Nokturnal and 67 Special.

The tiltmeter on the north flank of Pu'u 'O'o cone recorded slowed DI deflation.

The measurements were made at three sites, using falling bodies, a water tube 580 feet long (to record changes in tilt), a borehole tiltmeter and a highly sensitive gravimeter.

The modern electronic tiltmeter, which is slowly replacing all other forms of tiltmeter, uses a simple bubble level principle, as used in the common carpenter level.

The one at Popocatepetl is so sensitive that if you had a 3,000-foot bar of steel, and slipped a nickel under one end, the tiltmeter at the other end would detect it.

The graph shows this repeated action, with a pattern of swelling of the main chamber (recorded by the tiltmeter), draining of that chamber, and then an eruption of the adjoining vent.

Usually, though not always, these changes propagate through the magma conduit from the summit to the east rift eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu'u 'O'o, delayed by several hours.