Subsidence events in the Krafla area, North Iceland, 1975-1979

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E. Tryggvason


In the inflation-deflation sequence of the Krafla magma chamber since its beginning in 1975, 12 deflation or subsidence events have been identified until May, 1979. The tilt and distance measurements relating to these subsidence events are discussed in some detail. All of these subsidence events are associated with horizontal magma flow along the N-S trending fissure zone, which goes through the central part of the Krafla caldera, to form a dike 3 to 5 m wide, 80 km long, and 1.0 to 2.5 km high from the bottom to the top. The total volume of magma, which flowed out of the Krafla magma chamber during these 12 events, is estimated as 481 x 106 m3, whereof 407 x 106 m3 are estimated to have flowed northwards, 72 x 106 m3 southwards and about 2 x 106 m3 came to the surface as basaltic lava.

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Tryggvason, E. (1980). Subsidence events in the Krafla area, North Iceland, 1975-1979. Journal of Geophysics, 47(1), 141-153. Retrieved from
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