B. Székely1,2, E. Király2, D. Karátson3,4, T. Bata3
1 Institute of Photogrammetry and Remote Sensing, Vienna University of
Technology, Vienna, Gusshausstr. 27-29, A-1040 Wien, Austria
Telephone: (43) 1 58801-12251
Fax: (43) 1 58801-12299
2 Department of Geophysics and Space Science, Eötvös Loránd University, Budapest, H-1117 Budapest Pázmány P. sétány 1/c.
Telephone: (36) 1 209-0555/6651
Fax: (36) 1 372-2927
3 Department of Physical Geography, Eötvös Loránd University, Budapest, H-1117 Budapest Pázmány P. sétány 1/c.
Telephone: (36) 1 381-2111
Fax: (36) 1 381-2112
4 Geoscience Centre, Georg-August University of Göttingen, Goldschmidtstr. 1-3,
D-37077 Göttingen, Germany
The availability of the Shuttle Radar Topography Mission (SRTM) Digital Terrain Model (DTMs) paved the way of new approaches in volcanic geomorphology. Because of their relatively well definable geometric form, the gradually degrading volcanic edifices shaped by the surface processes are suitable targets for morphometric studies. After the cessation of the volcanic activity the relatively steep slopes are gradually changing together with the height of the form. This process can be studied by the categorisation of the volcanic cones and parameter estimation on the different group members. During the degradation of volcanic edifices the characteristic properties of the cones change, so the geometric modelling of their surface may result in parameters that are meaningful in the understanding of these processes. Our study area, the San Francisco Volcanic Field (SFVF), is a ca. 4500 km2-large volcanic region situated around the San Francisco stratovolcano in Arizona near Flagstaff (USA; Fig. 1).
The SFVF hosts some 600 scoria and lava domes, numerous lava flows with extensive volcanic ash deposits. Because of the wide range in size and age, as well as contrasting degradation of these volcanic features, several authors have analysed them in order to derive general rules of their lowering. Morphometric parameters were determined that were expected to be suitable to fulfil this requirement. In his pioneering work, Wood (1980a,b) considered 40 scoria cones, while almost two decades later Hooper and Sheridan (1998) included 237 features in their study. Their manual morphometric analyses were based on topographic maps that are time consuming, therefore their limited scope can now be extended with the availability of digital data.