I know that one of the first things that geologist looks for in a disaster is a geological map of the affected area. Below, are sources that I have so far been able to find of the disaster area. Most of the online publications can be found using Google Scholar. Unfortunately Reddit will not let me include links for some reason. If a person can not find the links, they can DM me.
Best source, so far, for local geology of the Rasuwa, Nepal – Gyirong Port Corridor - Has Online PDFs
It contains detailed description of local the geology. Highly recommended. - online
Kharti, A., 2010. Engineering Geology and Geotechnical Investigation of Rasuwagadhi Hydroelectric Project. Doctoral dissertation, Tribhuvan University
Has some local geological maps of Nepal – Gyirong Port Corridor - online
Shrestha, K., 2012. Geological, Engineering Geological and Geotechnical Studies of the Upper Trishuli–2 Hydroelectric Project Rasuwa, Central Nepal Doctoral dissertation, Tribhuvan University
Decription of regional geology with regional geologic maps - Has online PDFs
Rai, S.M., 1998. étude structurale, métamorphique, géochimique et radiochronologique des nappes de Katmandou et du Gosainkund, Himalaya de Népal central (Thés d'université thesis), Univ Joseph-Fourier, Grenoble, 244 p.
Rai, S.M., 2001. Geology, geochronology and radio chronology of the Kathmandu and Gosainkund Crystalline Nappe, Central Nepal Himalaya. Journal of Nepal Geological Society, Vol. 25 (Sp. Issue), pp. 135–155.
Rai, S.M., 2003. Distribution of boron in the rocks of Central Nepal Himalaya. Journal of Nepal Geological Society,Vol. 28. 58 p.
Regional geology - Not found online - not evaluated
Colchen, M., Le Fort, P., Pêcher, A., 1980. Carte geologique Annapurna- Manslu-Ganesh Himal du Nepal Echelle 1:2,00,000, Centre National de la Recherche Scientifique, Paris 136 pp.
Colchen, M., Le Fort, P., Pêcher, A., 1986. In: Recherches geologiques dans l'Himalaya du Nepal Annapurna Manaslu, Ganesh Himal. Paris Editions du Centre National de la Recherche Scientifique, Paris, 136 pp.
Upreti, B.N. and Le Fort, P., 1999. Lesser Himalayan crystalline nappes of Nepal: Problems of their origin. in Himalaya and Tibet: Mountain Roots to Mountain Tops, edited by A. Macfarlane and R. B. Sorkhabi, Spec. Pap. Geol. Soc. Am., 328, 225 –238.