This book strives to fill in the following gaps. First, there is no comprehensive descriptive treatment of deposits emplaced by lahars, debris avalanches, and muddy floods at volcanoes. Second, until now there has not been a comprehensive effort to describe and differentiate the full range of fragmental deposits on volcanoes—the initially wet volcaniclastic mass-flow and fluid-flow deposits usually studied by geomorphologists and sedimentologists, the initially dry pyroclastic mass-flow, fluid-flow, and tephra-fall deposits studied by volcanologists, and the deposits transported and deformed by flowing glacier ice that are studied by glacial geologists. All these deposits are mainly composed of volcaniclastic particles, are deposited on the flanks of volcanoes, all these deposits are mainly composed of volcanic particles and can closely resemble one another. Third, all these processes have vastly different hazard implications, so a means for reliable identification of past processes from deposits is critical for hazard assessment.
