The prehistoric landslide (one of the world's hugest, by the way) has been called "Saidmar(r)eh" in 1937, probably after the river that was dammed by it, see https://geology.com/landslides/saidmarreh-landslide.shtml To me, it is not clear yet whether there is also a place called like that. The only village inside the landslide area seems to be https://www.openstreetmap.org/node/3291475772 Notably, the one paper that was obviously published by locals (?) more recently spells "Seimareh" (Shoaei, Z. and Ghayoumian, J., 1998), however.