Earth-prints repository, logo   DSpace

About DSpace Software
|earth-prints home page | roma library | bologna library | catania library | milano library | napoli library | palermo library
Please use this identifier to cite or link to this item:

Authors: Kueppers, U.*
Scheu, B.*
Spieler, O.*
Dingwell, D. B.*
Title: Field-based density measurements as tool to identify preeruption dome structure: set-up and first results from Unzen volcano, Japan
Title of journal: Journal of Volcanology and Geothermal Research
Series/Report no.: 141 (2005)
Publisher: Elsevier
Issue Date: 1-Mar-2005
DOI: 10.1016/j.jvolgeores.2004.09.005
Keywords: field-based density measurements
Unzen volcano
explosive eruption
block-and-ash flow
fragmentation behaviour
Abstract: For an improvement in the quality of conduit flow and dome-related explosive eruption models, knowledge of the preeruption or precollapse density of the rocks involved is necessary. As close investigation is impossible during eruption, the best substitute comes from quantitative investigation of the eruption deposits. The porosity of volcanic rocks is of primary importance for the eruptive behaviour and, accordingly, a key-parameter for realistic models of dome stability and conduit flow. Fortunately, this physical property may be accurately determined via density measurements. We developed a robust, battery-powered device for rapid and reliable density measurements of dry rock samples in the field. The density of the samples (sealed in plastic bags at 250 mbar) is determined using the Archimedean principle. We have tested the device on the deposits of the 1990–1995 eruption of Unzen volcano, Japan. Short setup and operation times allow up to 60 measurements per day under fieldwork conditions. The rapid accumulation of correspondingly large data sets has allowed us to acquire the first statistically significant data set of clast density distribution in block-and-ash flow deposits. More than 1100 samples with a total weight of 2.2 tons were measured. The data set demonstrates that the deposits of the last eruptive episode at Unzen display a bimodal density distribution, with peaks at 2.0F0.1 and 2.3F0.1 g/cm3, corresponding to open porosity values of 20 and 8 vol.%, respectively. We use this data set to link the results of laboratory-based fragmentation experiments to field studies at recently active lava domes.
Appears in Collections:Papers Published / Papers in press
04.08.07. Instruments and techniques

Files in This Item:

File Description SizeFormatVisibility
jvgr 141 (2005) 65-75_Kueppers et al_Field based density measurements.pdfPublisher's version693.82 kBAdobe PDFView/Open
Kueppers_density_jvgr.pdfPost-print1.12 MBAdobe PDFView/Open

This item is licensed under a Creative Commons License
Creative Commons

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Share this record




Stumble it!



Valid XHTML 1.0! ICT Support, development & maintenance are provided by CINECA. Powered on DSpace Software. CINECA