According to Alvin Benson, volcanic ash and lava can be carried up to bury cities (Berger 57-61), and Nephi records that the earth was carried up on the city Moronihah (3 Nephi 8:10) and not down, as one would expect in a landslide. [Alvin K. Benson, "Geological Upheaval and Darkness in 3 Nephi 8-10," in The Book of Mormon: 3 Nephi 9-30, This Is My Gospel, p. 64]
“A Great Mountain”
While the word "volcano" never appears in the Book of Mormon, it is worthy of note that in the midst of all sorts of descriptive terms relative to volcanic and seismic activity in 3 Nephi 8, we do find reference to the fact that "in the place of the city [of Moronihah] there became a great mountain. Ben Olsen, who has done some surface geological work in Mexico and interpretation of stratigraphy and subsurface seismic data in parts of southern Mexico, Guatemala and Belize, is amazed at the number of possible geological agreements between the Book of Mormon text and these lands. . .
The dominant obvious geological structural elements in the area are the active volcanoes and an active left-lateral, or strike slip fault system crossing central Guatemala in an east-west direction (see illustration). The two major faults, the Polochic and Motagua, and the volcanism are associated with the continuing collision of two oceanic plates in the area, the Cocos and the Caribbean plates. Subduction of the northeast-moving Cocos oceanic plate beneath Central America and Mexico and the intersection and collision of the subsea East Pacific Rise with the west coast of the North American continent (see illustration), combine to make the Mexico-central America area a perpetual unstable earthquake and volcanic zone which has been active for millions of years . . . . Movement along the major fault system in Guatemala, subduction of the oceanic plates under the west coast of Mexico, eruption of one or more volcanoes in the area and perhaps a major hurricane with its attendant tornadoes could account for the damage noted in 3rd Nephi. . . .
Just as volcanoes can quickly disappear by explosive forces, they can also form very quickly by upwelling of hot magma. [Ben L. Olsen, Some Earthly Treasures of the Book of Mormon, pp. 51-52, 56 Unpublished]
3 Nephi 8:10 A great mountain (Volcanic and Seismic Activity) [Illustration]: Southeast Mexico - Guatemala Surface Geologic Map. Compiled from 1960 Mexican and 1970 Guatemalan geologic maps. [Ben L. Olsen, Some Earthly Treasures of the Book of Mormon, Map 5, Unpublished]
3 Nephi 8:10 A great mountain (Volcanic and Seismic Activity) [Illustration]: Earth Plate Movements Affecting the Americas. (From the book, Exploring our Living Planet, National Geographic Society, p. 58, 1983.) [Ben L. Olsen, Some Earthly Treasures of the Book of Mormon, Map 6, Unpublished]