In Lake Baikal coastal shallow waters (shelves) and underwater slopes are developed; the bed of three cavities of the lake is expressed; there are underwater shoals and underwater mountain ranges. The shoals of Lake Baikal in different places are from several dozens to several hundreds of metres wide, in the delta parts of the Selenga, Upper Angara and Barguzin rivers up to several kilometres wide. The total area of the shallow places of the lake makes up about 3% of the Baikal area (about 900 sq. km).
The deepest places of Lake Baikal are near the eastern shore of Olkhon island, on the coast between Izhimei and Khaara-Khushun capes, 8-12 km offshore to the east. The smallest depth of the open lake is located over the Posolskaya shoal which is almost in the middle of the Baikal. G.Yu. Vereshchagin points out that the minimum depth found by him over the shoal is 34 m, but N.P. Ladokhin has found the depth of 32 m. Small depths of about 260 m are over the underwater Academichesky mountain range which separates the middle cavity of the lake from the northern one, as well as over the Selenginskaya bulkhead which separates the southern cavity of the Baikal from the middle one. There the minimum depth is 360 m. The Academichesky range is the most impressive among the underwater ranges of Lake Baikal. It is about 100 km long, the maximum height over the Baikal bottom is 1,848 m.
The underwater Srednebaikalsky (Selenginsky) mountain range is situated opposite the Selenga delta. It is about 100 km long, its maximum height is about 1,374 m.