The forth meeting was held as part of the IAVCEI General Assembly 2008 (17-22 August 2008, Reykjavik, Iceland) and mainly focused on:
1) Discussion of the results from the Commission field workshop on the determination of the maximum clast carried out in Ecuador (3rd meeting, Salcedo, 2006).
2) Publication of the results of the Ecuador workshop both as a short communication and as an IAVCEI official report (both peer reviewed).
3) Improving the data set of the IAVCEI Commission to include data from the following eruptions: Mt Spurr 1992 (Alaska), Fuego 1974 (Guatemala), El Chichon 1982 (Chile), Etna 2001 (Italy), Mt St Helens 1980 (USA).
4) When available, adding the web-site links of wind profiles to eruption data set.
5) Compilation of a software for the extrapolation of wind profiles above the volcanic vent.
6) Compilation a database for thresholds of hazardous tephra accumulation.
7) Make sure there is consistency between the sampling protocol of our Commission and the IVHHN.
8) Link and data sharing with other working groups (Eruption Source Parameters Group, International Volcanic Health Hazard Network) and IAVCEI Commissions (Statistics in Volcanology, Commission on Explosive Volcanism).
We have also discussed the possibility of carrying out sensitivity analyses both on field and modeling procedures:
9) Sensitivity analyses on the effects of the distribution and number of field data on the determination of eruptive parameters.
10) Modeling exercise to reproduce isopleth maps and compare them with the model of Carey and Sparks (1986).
11) Comparison of the outputs of different sedimentation models using the same initial conditions (i.e. same eruption parameters). Such a test is work in progress at Instituto Nazionale di Geofisica e Vulcanologia (Italy) using the following models: TEPHRA2, HAZMAP, FALL3D, PUFF and VOLCALPUFF; and scenarios: Etna 1998 and 2002.