IASPEI - Picture Gallery

IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS003 Poster presentation 1880
An experimental model of data receiver for gravitational disturbance
research and earthquake prediction with 3 to 16 days forestalling
Prof. Nikolay Egorov
Faculty of Applied Mathematics and Control Process St.Petersburg State University
Valeriy Smirnov, Boris Bogdanovich
Gravitational field of the Earth is researched for more than 300 years. Nowadays reliable mathematical
models and data analysis methods are developed, which makes possible to solve various gravimetric
problems. Using advanced gravimetric methods we can analyze time-dependent changes of gravitational
force: changes caused by tidal effects and Earth's rotation; and caused by mass redistribution inside the
Earth. All gravitational disturbances may be divided into 2 groups: caused by effect of external (space)
objects, like the Sun, the Moon, etc.; caused by movement of tectonic masses in the Earth's crust and
mantle. The latter movements causes intense earthquakes. Modern experimental techniques of
gravitational disturbances recording are strictly limited both for disturbances of tectonic origin, and for
ones of space origin. Possible recording of local gravitational disturbances in different regions of the
Earth would make it possible to predict probable earthquake sources with some days forestalling, which
could save their lives for hundreds thousands of people. The developed data receiver for gravitational
disturbance recording is a dynamical electro-mechanical device, which provides the ability to determine
direction on the sourced of gravitational impact. The main element of the data receiver is a brass
gyroscope, operating in negative acceleration mode. In this rotation mode the gyroscope reacts on
change of the Sun (Moon) position relating the data receiver by change of period of revolution. As a
result the output signal is changed and may be recorded using a plotter. The sensitivity level depends
also on: angular velocity of rotation; length of deceleration pulse; direction angle to possible source of
gravitational impact. The data receiver shows high sensitivity level in recording small gravitational
impacts from space objects. It is possible to record also high disturbances caused by internal effects. In
principle, all tectonic movements may change gravitational potential of the Earth. Using map of the
Earth's crust breacs, we have carrried out an experiment of data receiver orientation on some of
tectonically active areas. We have registered several high gravitational impacts, with 400 to 500 μs
change of preiod of revolution. (In contrast, for space gravitational impacts, the change was about 75
to 200 μs.) The times of recording were correlated with information about earthquakes. In all cases the
signals were recorded with 3 to 10 (and more) days forestalling. E.g., for earthquake in Iran, 2 April
2006, the signal was recorded on 29 March 2006. Now an experimant is in progress, on scanning and
monitoring some seismologically active Earth's regions using the data receiver.
Keywords: gravitational, disturbance, earthquake