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Explosions details (2008b)

Activity

Normal Strombolian

Dates of the explosion

Beginning

End

 

June 4rd 2008    21:34 GTM

June 4rd 2008    21:54 GTM

Explosion pressure

0.7 bar (source) 32Pa (ROC station)

Initial particle velocity

31.5 m/s

Geophysical data (2008b)

Seismic displacement

 

Acoustic pressure

> 10Pa

Radiometer amplitude

 

Thermal Video

 

Sound azimuth graphs relative to 48 hours long period of sampling: from June 3rd at 15:00 GMT, when the plastic sheets were deployed, to June 5th at the same hour when they were taken back. The dataset is relative only to SW explosions. The grey bands indicating no sampling period; white crossed squares and the black one (3) that have pressures greater than 10 Pa, are explosions (11 explosive events during the three full days detected by the infrasonic array). Numbers next to the squares (1 to 6) indicates the possible six explosive events able to give the bombs distribution. The black full square is the more plausible explosion.

Seismic and pressure trace of the explosive event which generated the scoria bombs distribution.

Sample quantifications (2008b)

Description

Decimetric bombs quenched in situ from a normal Strombolian explosion

Particle morphology

Angular

Particle size

3 Data tables

Minimum size of holes counted (pixel)

10

Number of counted holes
Hole 2D integrated distribution (%)
Holes Number density

1 Data table

Number of images (x magnification x area)

3 Data tables

Hole equivalent diameter
Hole area
Hole perimeter
Hole long axis
Hole short axis
Hole orientation
Image magnification

3 Data tables

Bins
Na
Nv

3 Data tables

Tarps location

 

Total digital “map” of the plastic sheet Tarp_1 obtained from the camera. b) Image processing made on the total plastic sheet reducing holes left by bombs heat in black and the plastic in white. The resolution is 1pix/mm. c) Processing of the four parts forming the sheet with an increased magnification (0.5 pixel/mm). d) Higher magnificated portions (0.13 pixel/mm) of a portion of the sheet. The subsequent higher magnifications are necessary to be sure to count all the holes.

 

 

 
     
   
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