Classification of explosive volcanic primary and secondary deposits (tefra and secondary deposits) on the basis of their structural and textural characteristics. Main parameters for their quantitative description: tools and measurement techniques. Archiving procedures of field data. Field analysis of fall-out deposits: principles and techniques of stratigraphic correlation and areal mapping. Field analysis of welded and non-welded pyroclastic density current (PDC) deposits: principles and techniques of stratigraphic correlation and areal mapping. Field analysis of secondary volcanic deposits (lahar deposits) measurement tools and techniques. Procedures for the measure of eruptive parameters (volume of erupted magma and eruptive intensity). Sampling techniques of pyroclastic deposits and pyroclastic materials. Laboratory analysis for the study of loose and welded pyroclastic deposits (granulometric analysis, component analysis, micro-textural analysis). Measurement of density / total vesicularity of clasts; microscopic textural analysis of micro-vesicularity. Quantitative reconstruction of eruptive activity (eruptive history) aimed at the probabilistic evaluation of volcanic hazards.