1,720,968 research outputs found
A user-friendly, dynamical environment for remote data browsing and analysis of multiparametric geophysical data
No full textSpectral and dynamical evolution of volcanic tremor: looking at the preparation timescale of the 5 April 2003 explosion at Stromboli Volcano
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Development of a forecasting approach using stochastic methods applied to the Soufrière Hills volcano
No full textWithin the framework of the EU-project MULTIMO (Multi-disciplinary monitoring, modelling and forecasting of volcanic hazard), a stochastic methodology aiming at forecasting volcanic activity in the near future is currently under development. This approach is based on geostatistical concepts and allows the characterisation of the behaviour for time series recorded at active volcanoes.
The following steps are considered for analysis and simulation of discrete and continuous variables taken from multi-parametric data sets:
(a) analysis and parameterisation of time behaviour by variogram calculation,
(b) stochastic simulation for Monte Carlo forecasting and
(c) kriging analysis for estimation of time components related to precursors of volcanic activity
STP: What about dynamics?
No full textThe origin of volcanic tremor is still the subject of vigorous scientific debate. One of the most recent models, by Ripepe and Gordeev, suggests that volcanic tremor is related to the coalescence of bigger gas bubbles from a layer of smaller ones in the magma foam, forced by a structural barrier. The evidence of this model is mainly related to the relationship between the seismic signal and infrasonic waves. These must be generated by the same dynamical process, although the latter are related to a successive phase, i.e. the bursting of the bubbles at the magma-air interface.
Previous studies by Carniel and Di Cecca furnished evidence that volcanic tremor can be considered as a state variable of a deterministic dynamical system of "low" dimension. If the pressure signal is related to the same dynamical process, the two time series should not show too different dynamical behaviour.
On 19 June 1999, an experiment was carried out, recording simultaneously not only seismic and pressure waves, but also thermal data, using a Minolta/Land Cyclops 330 infrared thermometer aimed at one of the vents in NE Crater. Preliminary results from the dynamical analysis of the resulting time series are presented and discussed
DEVIN : a simulator of volcanic events considered in terms of a stochastic punctual process
No full textWithin the framework of the EU-project MULTIMO (Multi-disciplinary monitoring, modelling and forecasting of volcanic hazard), a software called DEVIN (Deducing Eruptions of Volcanoes In Near future) aiming at forecasting volcanic activity in the near future is currently under development. DEVIN is based on geostatistical concepts and allows the characterisation of the behaviour of time series recorded at active volcanoes. The functions of DEVIN used for the simulation of discrete and continuous variables are the following:
- Time behaviour analysis by variogram calculation.
- Time behaviour parametrisation by variogram modelling.
- Stochastic simulation for Monte Carlo forecasting and data reconstruction (i.e., gap filling).
- Kriging analysis for estimation of time components related to volcanic activity.
- Statistical analysis and visualisation of modelling results.
DEVIN is an open source software, running under Scilab, that applies specific routines written in C and Fortran in order to avoid time consuming computations. DEVIN is a tool which provides the possibility to model time behaviour as characterised from multi-parametric data sets. It, therefore, should reduce the uncertainty in forecasts of volcanic activity
Dynamical tools for the analysis of long term evolution of volcanic tremor at Stromboli
No full textStromboli is characterized by persistent seismic activity, both in terms of tremor and of discrete events associated with moderate explosions defining the so-called "Strombolian activity". This kind of permanent activity suggests the probable existence of a dynamical system governing the volcano. The purpose of this paper is to extract information on the "Stromboli dynamical system" from the seismic recordings. The analysis is carried out using the theory of non-linear dynamical systems and the delayed coordinates phase-space reconstruction. Several methods are presented and discussed in order to analyze volcanic tremor data in this framework; finally the time evolution of the computed parameters, both in the long term and close in time to paroxysmal phases, is presented and discussed. Evidence for a strong deterministic component in the dynamics of the volcano is shown.JCR Journalope
Utilization of passive seismic methods for a rapid dynamical characterization of structures: the Salt bridge case study
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