Surface deformations during the 1996 Karymsky Volcano eruption

Abstract

Instrumental measurements suggest that significant horizontal tensile strains of the Earth's surface had began 6 years prior to the January 1, 1996 Karymsky eruption at a speed of 4·10-6 D/year, where D baseline means length in mm. After the events in January 1996, the nature of deformations remained unchanged during 7 years. Stretching of the Earth's surface continued at a speed of about 3·10-6 D/year. In 2003 stretching was replaced with compression and had reached 7.5·10-6 D/year by 2007. The beginning of compression approximately coincides with the termination of outpouring of small portions of lava from a crater. After 2007, sign-variable deformations are observed; stretching alternates with compression and vice versa. During that period the volcano was producing weak explosions with no lava effusions.