Remote sensing morphometric measurements of cinder cones in Tolbachik volcanic field (Central Kamchatka)

Sammanfattning

Morphometric measurements of cinder cones can be derived from digital topographic data, field research or remotely sensed information. Analyses of this data have proven an efficient tool for determining relative dates of cinder cones and the erosional processes affecting them. This paper assesses and compares the capabilities of remotely sensed data for morphometric measurements of the modern and previously formed cinder cones of the Tolbachik volcanic field in Kamchatka. The tephrochronological and 14C dating of the older cinder cones (most of them post glacial) permitted the comparing their morphological characteristics with the recent ones. The present research examines the morphometric characteristics among nine monogenetic cones within the Tolbachik volcanic field, measured from digital elevation model (DEM) derived from optical satellite data (ASTER) and radar data (SRTM) and approved by field GPS measurements. Fournew cinder cones were recently formed during last basaltic eruption occurred in 1975-1976 and five old cones were formed during last 1700 years. For every studied cinder cone the calculations of morphometric parameters were made on the base of remotely sensed data and digital elevation model. Morphometric measurements included the cone height (h), average cone slope (s), major-axis diameter (dmj), short axis diameter (dmi), and height-width ratio (h/D), where D=(dmj+dmi)/2. The results of morphometric measurements of the cinder cones were presented for ASTER-based DEM (15 m of spatial resolution) and SRTM DEM (90 m of spatial resolution). The field GPS measurements on the base of Sirf III chipset (horizontal position with accuracy about 2.5 meters and elevation with accuracy about 5 meters) of 40 locations were performed to provide geodetic reference for DEM processing as well as to validate the further derived morphometric parameters (45 locations). The evaluation of RMS errors (horizontal and vertical) of two digital elevation models was carried out by comparing of ASTER-derived DEM and SRTM DEM to field GPS locations. The inspection of main morphometric parameters of slope and height/base ratio accordingly to ASTER-based DEM shows significant correlation with age groups of cones formation. For all cones highest slope values correspond to recent cones. Average slope for recent cones group is 31.9 (ASTER) and 28.2 (SRTM) when old cones group shows considerably smaller average slope values: 26.3 and 23.1, respectively. The tendency of correspondence of high values to youthful constrictions also traced for height-base ratio. The results of morphometric analysis presented in this study allow determination of relative age of cinder cones and provide a basis to guide future calibration between radiometric dating of absolute ages and morphometric method

Nyckelord

remote sensing; DEM; cinder cones morphometry

Konferens

The 33rd International Geological Congress

UKÄ forskningsämne

Miljö- och naturvårdsvetenskap

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/21667