Alteration of volcanic rocks and changes in physical-mechanical properties on the South-Kambalny thermal field (South Kamchatka)Julia Frolova, Michael Chernov, Sergey Rychagov, Ruslan Kuznetsov and Ksenia SurovtsevaE3S Web Conf., 98 (2019) 08002DOI: https://doi.org/10.1051/e3sconf/20199808002