US4904943A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for detecting long waves and predicting earthquakes
Assignee: National Institute of Information and Communications Technology
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Filing: 1988-09-07
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Granted: 1990-02-27
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Expires: 2008-09-07
Abstract
Abstract A method for detecting earthquakes comprises the steps of picking up pre-earthquake long waves or earth currents at four or more observation points located underground or at the sea bottom, carrying out a computation based on the interrelation among the so-obtained= signals to obtain the three-dimensional distribution of the sources and intensities of the long waves or earth currents, and predicting the focal region, scale and time of occurrence of earthquakes from the time-course variation in the so-obtained three-dimensional image of the wave source.
Inventors
- 👤 Kozo Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:45
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/01; G01V3/00; G01V3/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
173 words
A method for detecting pre-earthquake long electromagnetic waves and for predicting earthquakes based thereon, comprising the steps of: locating a plurality of observation points at which long waves may be detected; installing an antenna at each of said plurality of locations; sensing the presence of said long waves by each of said antennas; transmitting a signal indicative of said long waves from each antenna to a storage device; storing data representing the transmitted signal in said storage device; computing the value of a phase shift time at which a correlation function between two of said signals becomes maximal; determining the location of a rotational hyperboloid of two sheets having its foci at the two observation points from which the sensed signals are obtained; repeating the computing and determining steps for at least one additional pair of sensed signals and observation points; determining the intersection of the hyperboloids; and predicting the occurrence, location and magnitude of an earthquake based on both the intersection of the hyperboloids and the correlation coefficient of said correlation function.
Claim 2
Independent Claim
173 words
A method for detecting pre-earthquake long electromagnetic waves and for predicting earthquakes based thereon, comprising the steps of: locating a plurality of observation points at which long waves may be detected; installing an antenna at each of said plurality of locations; sensing the presence of said long waves by each of said antennas; transmitting a signal indicative of said long waves from each antenna to a storage device; storing data representing the transmitted signal in said storage device; computing the value of a phase shift time at which a correlation function between two of said signals becomes maximal; determining the location of a rotational hyperboloid of two sheets having its foci at the two observation points from which the sensed signals are obtained; repeating the computing and determining steps for at least one additional pair of sensed signals and observation points; determining the intersection of the hyperboloids; and predicting the occurrence, location and magnitude of an earthquake based on both the intersection of the hyperboloids and the correlation coefficient of said correlation function.
Claim 3
Dependent Claim
21 words
A method for detecting earthquakes according to claim 1 wherein said observation points are separated from each other by 100-500 km.
Claim 4
Dependent Claim
24 words
A method according to claim 1, wherein at least one of said antennas is a monopole antenna mounted in a hole in the ground.
Claim 5
Dependent Claim
21 words
A method according to claim 1, wherein at least one of said antennas is a dipole antenna on the sea floor.
Claim 6
Dependent Claim
21 words
A method according to claim 1, wherein at least one of said antennas is a loop antenna on the sea floor.
Claim 7
Dependent Claim
20 words
A method according to claim 1, wherein there are substantially no accompanying noise waves at said plurality of observation points.
Claim 8
Dependent Claim
16 words
The method according to claim 1, wherein at least four observation points and antennas are utilized.
Claim 9
Dependent Claim
26 words
A method according to claim 1, wherein the computing and determining steps are continuously repeated to obtain a three dimensional representation of the wave source region.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-26 | 1993-08-28 | 1994-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-26 | 1997-08-28 | 1998-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-26 | 2001-08-28 | 2002-02-27 | $7700.00 | Window Closed / Lapsed |