Section for Mineralogy, Petrology & Geochemistry

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Fragmentation Lab


Dr. Bettina Scheu
Dr. Ulrich Küppers
Laboratory Phone: +49 89 2180 4661


  • 4 Shock Tube Apparatus (fragmentation bombs): rapid decompression experiments at RT – 850°C, 0.1 – 50 MPa

4 Shock Tube Apparatus (fragmentation bombs)

  • Large low pressure tank (3 m long, 0.4m wide) and several high pressure autoclaves, separated by a set of 1-3 rupture discs
  • Rapid decompression experiments using Argon gas to analyse fragmentation behaviour (threshold, speed, efficiency) at 20°C - 900°C and 0.1 - 50 MPa
  • Phreatic Explosion experiments with water saturated samples, P&T sensors installed in the range of 20°C – 400°C and 0.1 – 25 MPa.
  • Measurement of Particle ejection speed
  • Analysis of natural samples and magma analogues
  • Full recoverage of particles -> GSD
  • Pulse-decay permeability measurements
  • several sample sizes (mm):   19x50, 25x60, 60x60, 34x70
  • high-speed video recording from 50 to >50.000 fps

Description of facility:

The shock-tube devices are tailor-made and can be operated with a variety of set-ups to investigate aspects of fragmentation behaviour or natural and analogue material as: fragmentation threshold, fragmentation speed and permeability via a pulse-decay method. The shock-tubes operate from room temperature up to 900°C and at pressures between 1 bar (atmospheric) to 50 MPa applied pressure using by default argon gas for pressurization (pressurization by nitrogen or H2O vapour is also possible). Depending on the set-up, the experiment is monitored by a varying number of pressure and temperature sensors. The experimental pyroclasts are fully recoverable and thus allow determining the fragmentation efficiency.

fraglab-1 fraglab-2

(e.g. Spieler et al., EPSL, 2004)

fraglab-4 fraglab-5
fraglab-6 fraglab-7



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