Publication Date:
2017-04-04
Description:
A Digital Terrain Model derived from high resolution Lidar data allows the determination of the morphometric and physical
parameters of a lava flow erupted from the Somma–Vesuvius volcano in 1944. The downstream variation of morphometric
parameters including slope, aspect, relative relief, thickness, width, and cross sectional area is analyzed, and the changes in
viscosity, velocity and flow rate are estimated. The aims of the analyses are to recognize different flow surfaces, to reconstruct the
flow kinematics, and to obtain information on the mechanism of emplacement. The results indicate that the 1944 lava flow can be
divided in three sectors: a near vent sector (NVS) characterized by a toe-like surface, an intermediate sector (IS) with an ‘a’ātype
brittle surface, and a distal sector (DS) with a sheet-like ductile surface. Lateral leveés and channels do not occur in NVS, whereas
they are well developed in IS. In DS, leveés increase with an increasing distance from the vent. Fold-like surfaces occur in NVS
and DS, reflecting local shortening processes due to a decrease in the slope of the substratum and overflows from the main channel.
IS and DS emplaced between March 18 and 21, 1944, whereas NVS emplaced on March 19 and partly covered IS. The
morphometric and physical parameters indicate that IS moved in a ‘tube’-like regime, whereas DS emplaced in a 'mobile crust'
regime. The IS to DS transition is marked by an increase in velocity and the flow rate, and by a decrease in thickness, width, cross
sectional area, and viscosity. This transition is due to an abrupt increase in the slope of the substratum. The estimated velocity
values are in good agreement with the measurements during the 1944 eruption. The analysis used here may be extended to other
lava flows. Some gravity flows (debris/mud flows, floods, and avalanches) have rheological properties and shapes similar to those
of lavas, and the same process-form relationships may apply to these flows. The approach used here may be therefore useful for
evaluating hazards from various gravity currents.
Description:
Published
Description:
223–235
Description:
1.10. TTC - Telerilevamento
Description:
3.6. Fisica del vulcanismo
Description:
5.4. TTC - Sistema Informativo Territoriale
Description:
JCR Journal
Description:
reserved
Keywords:
Lava flow
;
Gravity flow
;
Lidar
;
Digital Terrain Model (DTM)
;
04. Solid Earth::04.04. Geology::04.04.03. Geomorphology
;
04. Solid Earth::04.08. Volcanology::04.08.03. Magmas
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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