Energy budget for a rock avalanche: fate of fracture-surface energy
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A detailed energy budget of a rock avalanche at Lake Coleridge, New Zealand, included fragments as small as 70 nm in diameter in the debris particle-size distribution, and used ultrasonic disaggregation of agglomerates formed during emplacement of the deposit to properly sample the fine fragments created during the rock avalanche. Using the maximum likely value of potential energy released during the debris fall and runout, and minimum values of energy lost to friction and of energy used in creating new rock surface area by fragmentation, the energy budget showed a substantial energy deficit; the available potential energy almost matched the energy lost to friction, leaving very little energy available for creating the new surface. This deficit was much less prominent if sub-micron fragments were ignored as in earlier energy budgets, because about 90% of total fragment surface area occurred on sub-micron fragments. Close examination of possible sources of error in the calculated budget leads to the conclusion, supported by published data, that only a small proportion of the energy used to create new rock surface transforms to surface energy, while a large proportion of it remains available in the form of elastic body-wave energy.
KeywordsLake Coleridge rock avalanche: ultra-fine debris Agglomerates Energy budget Energy lost to friction Fracture surface energy Surface free energy
The first author was partly supported by the Hazards Toolbox (T6) Of Resilience to Nature’s Challenges, funded by the Ministry of Business, Innovation and Employment, New Zealand Grant Number RNC-011.
- Carpinteri A, Lacidogna G, Manuello A, Niccolini G, Schiavi A, Agosto A (2012) Mechanical and electromagnetic emissions related to stress-induced cracks. ExpTech 36(3):53–64Google Scholar
- Cook GK (2001) Rock mass structure and intact rock strength of New Zealand greywackes. MSc thesis. University of Canterbury, New ZealandGoogle Scholar
- Davies TRH (2018) Rock avalanches: processes, significance and hazards. Oxford Research Encyclopedia of Natural Hazard Science, Oxford University Press, OxfordGoogle Scholar
- Dunning SA (2006) Rock avalanches in high mountains. PhD Thesis, University of Luton, UK, 337pGoogle Scholar
- Hoagland RG, Hahn GT, Rosenfield AR (1973) Influence of microstructure on fracture propagation in rock. Rock Mech/Felsmech/Mech des Roches 5:77–106Google Scholar
- Hungr O (2006) Rock avalanche occurrence, process and modelling. In: Evans SG, Scarascia-Mugnozza G, Strom A, Hermanns R. (eds) Advanced research workshop: landslides from massive rock slope failure. NATO Science Series, IV Earth and Environmental Sciences vol 49. Celano, Italy, June 16–21, 2002, pp 243–266Google Scholar
- Lee JA (2005) Engineering geological investigation of the Lake Coleridge rock avalanche deposits, inland Canterbury. MSc(Eng Geol) thesis, University of Canterbury, New Zealand, 221pGoogle Scholar
- Ouchterlony F (1982) Review of fracture toughness testing of rock. SM Archives 7:131–211Google Scholar
- White AF, Blum AE, Schulz MS, Bullen TD, Harden JW, Peterson ML (1996) Chemical weathering rates of a soil chronosequence on granitic alluvium: I. Quantification of mineralogical and surface area changes and calculation of primary silicate reaction rates. Geochim Cosmochim Acta 60:2533–2550CrossRefGoogle Scholar
- Zgura I, Moldovan R, Negrila CC, Frunza S, Cotorobai VF, Frunza L (2013) Surface free energy of smooth and dehydroxylated fused quartz from contact angle measurements using some particular organics as probe liquids. J Optoelectron Adv Mater 15:627–634Google Scholar