Clay mineralogy of landslide occurrences in hydrothermally altered area: A case study of Durensari Area, Purworejo, Central JavaIlham Dharmawan Putra, Anastasia Dewi Titisari and Hitznaiti Zaidini Khul HusnaE3S Web Conf., 76 (2019) 02008DOI: https://doi.org/10.1051/e3sconf/20197602008