Image Gallery:
"Shaded Bouguer Gravity Map of the Eastern Mediterranean"

Michael Rybakov, Geophysical Institute of Israel
rybakov@gii.co.il

Our gravity network includes about 150 thousand data points collected from various sources. The Bouguer gravity values were compiled using a density of 2670 kg/m3 and the 1967 reference ellipsoid. Sea level was taken as the reference height and the water body was replaced by the same density as on land. Finally, the gravity network thus compiled was converted to a square grid with 2 km spacing using the Surfer Inverse Distance to a Power technique.

WHAT CAN WE LEARN FROM GRAVITY SURVEYS?

• Gravity anomalies are likely to be related to crustal type.

• Negative gravity values are typical for the continental crust of the African and Arabian plates. In the Eastern Mediterranean and Red Sea positive values are associated with oceanic crust.

• A pronounced elongated gravity high characterizes much of Cyprus, where oceanic ophiolites are documented. This anomaly, coinciding with the Cyprian arc, is bounded to the south by a chain of gravity lows, probably corresponding to the trench of the subduction zone.

• High values extend eastward on land to the Dead Sea Transform fault system ("DST"). We assume that this density difference existed before the DST motion was initiated. The development of the DST used the eastern boundary of the dense block as a weakness zone. On the other hand, the DST has broken up the crust and made it easier to uplift the low-density eastern block.

• A string of gravity lows corresponds to sedimentary basins in the transform valley.

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