HR: 1400h
AN: V23A-05    [Abstracts]
TI: Reconstruction of lava fields based on 3D and conventional images. Arenal volcano, Costa Rica.
AU: Horvath, S
EM: ertaale@gmail.com
AF: University of Loránd Eötvös (former), Dpt of Physical Geography, Budapest, Hungary, Budapest, 1117, Hungary
AU: * Duarte, E
EM: eduarte@una.ac.cr
AF: OVSICORI-UNA, Campus Heredia Costa Rica, Heredia, 3000, Costa Rica
AU: Fernandez, E
EM: efernan@una.ac.cr
AF: OVSICORI-UNA, Campus Heredia Costa Rica, Heredia, 3000, Costa Rica
AB: Conventional air photographs, multi-spectral images and a map scale 1:10 000 were used to upgrade Arenal volcano's lava field. Arenal volcano located in NW Costa Rica has been active for 39 years. Fifty two days after the initial explosive events that opened three craters on the west flank, lava flows were erupted from crater A (1050 m) in September, 1968 and continued flowing until November, 1973. These lavas were the most voluminous of the eruption and the effusion rate of lava was relatively high in this period. In April, 1974 lava flows were erupted from crater C (1460 m) and continue to present time. Younger lava flows extended over uncovered ground to the south and southwest in the 1980s and early 1990s and onto the northern slopes in the 1990s and 2000s. Lava flows are becoming shorter and narrower with time. Therefore, the centre of mass of the whole lava flow-field has migrated closer to the vent. Above crater C a cone has been growing steadily, reaching a height of 1670 m, 36 m higher than the prehistoric Arenal cone by 2004. After 39 years of continuous emission of lava flows, the profile of Arenal volcano consists of a duplet of cones whose summits are separated by less than 500 meters. Most of the build up around the new cone comes from varied lava flows. For near 30 years volcano monitoring staff (from OVSICORI-UNA) has recorded field observations of regular and extraordinary events, in paper. Several drafts maps have been used for teaching, academic presentations and for graphic explanations to specific audiences and to the general public. An upgraded version was needed. The purpose of this work is to present the most recent lava flows giving a visual presentation of them by computer methods. Combined SIG techniques (Arc View 3.3) and ERDAS produced a base map in which layers containing the recorded lava flows from the recent 16 years, were depicted. Each lava flow has its own characteristics: direction, year of origin, width, length, surface texture, chemical composition, type of lava, velocity, etc. With all this information and photographs; real, visual and topographic images of the position and characters of the 1990s and 2000s lava flows, were obtained . An illustrative poster will be presented along with this abstract to show the construction process of such tool. Moreover, 3D animations will be present in the mentioned poster.
UR: http:www.ovsicori.una.ac.cr
DE: 0370 Volcanic effects (8409)
DE: 1011 Thermodynamics (0766, 3611, 8411)
DE: 1034 Hydrothermal systems (0450, 3017, 3616, 4832, 8135, 8424)
DE: 8485 Remote sensing of volcanoes
SC: Volcanology, Geochemistry, and Petrology [V]
MN: 2007 Joint Assembly