geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Slope instabilities in Dolomieu Crater, Reunion Island; from seismic signals to rockfall characteristics


, : Slope instabilities in Dolomieu Crater, Reunion Island; from seismic signals to rockfall characteristics. Journal of Geophysical Research 116.F4

The seismic signals of hundreds of rockfalls within Dolomieu crater, Piton de la Fournaise volcano, Reunion Island, have been analyzed to investigate a possible link between physical rockfall-generating processes and associated seismic signal features. Moreover, indirect observation of rockfalls via the seismic signals they generate can provide useful data for studying volcanoes and the temporal variations of their structure. An increase in the number of rockfall events and their volumes might be an indicator of structural weakness and deformation of the volcano associated with potential eruptive activity. The study focuses on a 10 month period following the 6 April 2007 crater floor collapse within Dolomieu crater, from May 2007 to February 2008. For granular flows a scaling law is revealed between seismic energy and signal duration. A semiempirical approach based on both analytical analysis and numerical simulation of these flows shows that a similar scaling law exists between the difference of potential energy computed for an event and its propagation times and also emphasizes the effect of local topography on this scaling law. Simulated and observed data were compared to evaluate the proportion of potential energy dissipated in the form of seismic waves and confirm a direct link between the seismic energy and potential energy of a given granular flow. The mean ratio of seismic to potential energy is of the order of 10(-4) , comparable to the range of values observed in previous studies. A simple method based on these ratios is proposed to estimate the volumes of rockfalls from their seismic signal. Observed seismic energy and the frequency of rockfalls decreased at the beginning of the studied period and reached a stable level in July, thus suggesting a postcollapse relaxation time of Dolomieu crater structure of about 2 months from seismic signal analysis, which is confirmed by deformation data. The total rockfall volume over the study period is estimated to be 1.85 Mm3 .

US$29.90


Other references

Wolyce Ulyera; Ilunga Sendwe, 1974: Geologic hypotheses on Lake Tanganyika region, Zaire, drawn from ERTS imagery. NASA Special Publication: Pages 955-967. 1974.

Roth, J.V., 1996: Transesophageal atrial pacing in patients with permanent pacemakers. Anesthesia and Analgesia 82(5): 1109-1110

Zaalberg, O.B.; Weyzen, W.W.; Vos, O., 1963: Influence of excess of antigen on immunological tolerance in radiation chimaeras. Nature 197: 300-301

Stockinger, B.; Zal, T., 1997: T-cells with two T-cell receptors: are they important in autoimmunity?. Biochemical Society Transactions 25(2): 617-620

Gonzalez-Crespo, Jose, 2002: Evaluacion sensorial en quesos de cabra. Eighty one products of raw goat milk from 5 cheese factories were evaluated for 6 panelists by INDO sensory evaluation test. The visual attributes of samples were no important relevance as good estimate of global quality in sensory evaluation. Sig...

Margolis, M.; Parker, P., 1972: The stork fable--some psychodynamic considerations. Journal of the American Psychoanalytic Association 20(3): 494-511

Leveille, G.A.; Sauberlich, H.E., 1961: Influence of dietary protein level on serum protein components and cholesterol in the growing chick. The influence of dietary protein level on body weight, total serum protein, protein components and serum cholesterol was studied in the growing chick. A semi-purified diet was employed in which sesame oil meal supplemented with lysine served as th...

Einspahr D.W., 1968: Growth and nutrient requirements of hybrids between populus canescens d and populus tremuloides d breeding nitrogen potassium magnesium phosphorus calcium. Genetics & Physiology Notes: 16

Buschhaus, C.; Herz, H.; Jetter, R., 2007: Chemical composition of the epicuticular and intracuticular wax layers on the adaxial side of Ligustrum vulgare leaves. Previous research has shown that cuticular triterpenoids are exclusively found in the intracuticular wax layer of Prunus laurocerasus. To investigate whether this partitioning was species-specific, the intra- and epicuticular waxes were identified...

Jonassohn, M., 1992: Bird-watching in Lithuania - a journey in time and space. Anser, 311: 11-16