RHEA (RHeophysics and Energy of magmAs) is a working group specialized on rheological magmatic properties.

Accurate prediction of the behavior of volcanic flows requires understanding its rheology. Magmatic numerical simulations aiming for fundamental research or hazard and risk assessment require a constitutive law. This last one is designed from simple physical assumptions or laboratory rheological measurements.

As its alias ‘mother of the Olympian gods’, RHEA wish to give birth to a new generation of numerical codes upheld with more accurate constitutive laws. It can be only achieved by pushing further the rheology of magmas. It recently experienced serious turnovers. Rheology of two phase magmas (i.e. Melt + bubbles or Melt + crystals) reached a degree of global comprehension which allows tackling the last major step, three phase magmas rheology. However, beyond the positive advancements new questions have raised and new topics need to be addressed. Among these questions are the rheology at low strain-rate, the impact and limits of crystal rigidity, strain/stress localization, stability of bubbles or the real sources of Non-Newtonian behavior.

Rheological results are partly dependent on methods, materials and strain-rates used. Each laboratory has favorite methodology, calculation methods or regime of flow. It sometimes generates absolute values that differ of a half order magnitude from one place to the other and makes comparison difficult.

With the present working-group we wish to namely, 1- reference and archive previous works on magma rheology into an open database operating under the best of nowadays possibilities in terms of analysis and communication, 2- gather each year all specialists of the field to discuss domains of investigation and define the hard-lines which require strong focus, 3- Increase collaboration and efficiency of teams sharing similar interests.