scholarly journals Examples of Multi-Sensor Determination of Eruptive Source Parameters of Explosive Events at Mount Etna

2021 ◽  
Vol 13 (11) ◽  
pp. 2097
Author(s):  
Valentin Freret-Lorgeril ◽  
Costanza Bonadonna ◽  
Stefano Corradini ◽  
Franck Donnadieu ◽  
Lorenzo Guerrieri ◽  
...  
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Real Time ◽  
Grain Size Distribution ◽  
Source Parameters ◽  
Radar Data ◽  
Mount Etna ◽  
Infrared Sensors ◽  
Paroxysmal Activity

Multi-sensor strategies are key to the real-time determination of eruptive source parameters (ESPs) of explosive eruptions necessary to forecast accurately both tephra dispersal and deposition. To explore the capacity of these strategies in various eruptive conditions, we analyze data acquired by two Doppler radars, ground- and satellite-based infrared sensors, one infrasound array, visible video-monitoring cameras as well as data from tephra-fallout deposits associated with a weak and a strong paroxysmal event at Mount Etna (Italy). We find that the different sensors provide complementary observations that should be critically analyzed and combined to provide comprehensive estimates of ESPs. First, all measurements of plume height agree during the strong paroxysmal activity considered, whereas some discrepancies are found for the weak paroxysm due to rapid plume and cloud dilution. Second, the event duration, key to convert the total erupted mass (TEM) in the mass eruption rate (MER) and vice versa, varies depending on the sensor used, providing information on different phases of the paroxysm (i.e., unsteady lava fountaining, lava fountain-fed tephra plume, waning phase associated with plume and cloud expansion in the atmosphere). As a result, TEM and MER derived from different sensors also correspond to the different phases of the paroxysms. Finally, satellite retrievals for grain-size can be combined with radar data to provide a first approximation of total grain-size distribution (TGSD) in near real-time. Such a TGSD shows a promising agreement with the TGSD derived from the combination of satellite data and whole deposit grain-size distribution (WDGSD).

scholarly journals FPLUME-1.0: An integral volcanic plume model accounting for ash aggregation

2016 ◽  
Vol 9 (1) ◽  
pp. 431-450 ◽  
Author(s):  
A. Folch ◽  
A. Costa ◽  
G. Macedonio
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Risk Mitigation ◽  
Source Parameters ◽  
Air Entrainment ◽  
Phase Changes ◽  
Column Height ◽  
Volcanic Plume ◽  
Eruption Column

Abstract. Eruption source parameters (ESP) characterizing volcanic eruption plumes are crucial inputs for atmospheric tephra dispersal models, used for hazard assessment and risk mitigation. We present FPLUME-1.0, a steady-state 1-D (one-dimensional) cross-section-averaged eruption column model based on the buoyant plume theory (BPT). The model accounts for plume bending by wind, entrainment of ambient moisture, effects of water phase changes, particle fallout and re-entrainment, a new parameterization for the air entrainment coefficients and a model for wet aggregation of ash particles in the presence of liquid water or ice. In the occurrence of wet aggregation, the model predicts an effective grain size distribution depleted in fines with respect to that erupted at the vent. Given a wind profile, the model can be used to determine the column height from the eruption mass flow rate or vice versa. The ultimate goal is to improve ash cloud dispersal forecasts by better constraining the ESP (column height, eruption rate and vertical distribution of mass) and the effective particle grain size distribution resulting from eventual wet aggregation within the plume. As test cases we apply the model to the eruptive phase-B of the 4 April 1982 El Chichón volcano eruption (México) and the 6 May 2010 Eyjafjallajökull eruption phase (Iceland). The modular structure of the code facilitates the implementation in the future code versions of more quantitative ash aggregation parameterization as further observations and experiment data will be available for better constraining ash aggregation processes.

scholarly journals Determination Of Spatial Grain Size Distribution Of A Sintered Metal

2009 ◽  
Vol 15 (2) ◽  
Author(s):  
H Amankwah ◽  
S Lauer ◽  
S Karichery ◽  
MD Ashraf-Ul-Alam
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Sintered Metal ◽  
Spatial Grain

scholarly journals FPLUME-1.0: An integrated volcanic plume model accounting for ash aggregation

2015 ◽  
Vol 8 (9) ◽  
pp. 8009-8062 ◽  
Author(s):  
A. Folch ◽  
A. Costa ◽  
G. Macedonio
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Risk Mitigation ◽  
Source Parameters ◽  
Air Entrainment ◽  
Phase Changes ◽  
Column Height ◽  
Volcanic Plume ◽  
Eruption Column

Abstract. Eruption Source Parameters (ESP) characterizing volcanic eruption plumes are crucial inputs for atmospheric tephra dispersal models, used for hazard assessment and risk mitigation. We present FPLUME-1.0, a steady-state 1-D cross-section averaged eruption column model based on the Buoyant Plume Theory (BPT). The model accounts for plume bent over by wind, entrainment of ambient moisture, effects of water phase changes, particle fallout and re-entrainment, a new parameterization for the air entrainment coefficients and a model for wet aggregation of ash particles in presence of liquid water or ice. In the occurrence of wet aggregation, the model predicts an "effective" grain size distribution depleted in fines with respect to that erupted at the vent. Given a wind profile, the model can be used to determine the column height from the eruption mass flow rate or vice-versa. The ultimate goal is to improve ash cloud dispersal forecasts by better constraining the ESP (column height, eruption rate and vertical distribution of mass) and the "effective" particle grain size distribution resulting from eventual wet aggregation within the plume. As test cases we apply the model to the eruptive phase-B of the 4 April 1982 El Chichón volcano eruption (México) and the 6 May 2010 Eyjafjallajökull eruption phase (Iceland).

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