A compact rock derived either from mudstone or shale, that has undergone a somewhat higher degree of induration than mudstone or shale but is less clearly laminated than shale and without its fissility, and that lacks the cleavage distinctive of slate.

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Alteration, slope-classified alteration, and potential lahar inundation maps of volcanoes for the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Volcano Archive

Identifies hydrothermally altered volcanic edifices and vulnerable areas downstream by mapping alteration on volcanoes, highlighting lahar prone watersheds using Global Digital Elevation Model data, and modeling via a lahar flow-fill modeling program