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Indian Ocean Geoid Low
The Indian Ocean Geoid Low (IOGL) is a gravity anomaly in the Indian Ocean. A circular region in the Earth's geoid, situated just south of the Indian peninsula, it is the Earth's largest gravity anomaly. It forms a depression in the sea level covering an area of about 3 million km2 (1.2 million sq mi), almost the size of India itself. Discovered in 1948 by Dutch people, Dutch geophysicist Felix Andries Vening Meinesz as a result of a ship's gravity survey, it remained largely a mystery until May 2023, when the weak local gravity was empirically explained using computer simulations and seismic data. Location, characteristics, and formation The gravity anomaly, or "gravity hole", is centered southwest of Sri Lanka and Kanyakumari, the southernmost tip of mainland India, and east of the Horn of Africa. Due to weaker local gravity, the sea level in the IOGL would be up to 106 m (348 ft) lower than the global mean sea level (reference ellipsoid), if not for minor effe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity Anomaly
The gravity anomaly at a location on the Earth's surface is the difference between the observed value of gravity and the value predicted by a theoretical model. If the Earth were an ideal oblate spheroid of uniform density, then the gravity measured at every point on its surface would be given precisely by a simple algebraic expression. However, the Earth has a rugged surface and non-uniform composition, which distorts its gravitational field. The theoretical value of gravity can be corrected for altitude and the effects of nearby terrain, but it usually still differs slightly from the measured value. This gravity anomaly can reveal the presence of subsurface structures of unusual density. For example, a mass of dense ore below the surface will give a positive anomaly due to the increased gravitational attraction of the ore. Different theoretical models will predict different values of gravity, and so a gravity anomaly is always specified with reference to a particular model. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
