Infrasonic Observations of the Hekla Eruption of February 26, 2000

INTRODUCTION On February 26-27, 2000 infrasonic signals associated with the eruption of the Hekla Volcano, Iceland, were recorded by the Swedish infrasound network. This network is operated by the Swedish Institute of Space Physics and consists of 4 stations located in Kiruna, Jamton and Lycksele in Northern Sweden and Uppsala in Central Sweden. Each station consists of an array of 3 modified Lidstrommicrophones (see Appendix 1) with a 7 Hz low-pass filter, so that the effective frequency range is 0.5 6 Hz. A sampling rate of 18 Hz is used at all stations. The microphones at each array are located in the corners of a right angle triangle, where the perpendicular sides are 75 m long and oriented East-West and North-South. Shelters reduce wind noise at each array element. The Kiruna and Lycksele array data may be accessed at http://callisto.space.umu.se. Geographical coordinates for the stations are given in Table I.