populous RCM, Rimouski-Neigette. Otherwise, the least populous RCM of the region is Les Basques, with only 9,000 inhabitants in 2011, a number which decreased by 1,300 since 1996, making it also the RCM with the highest annual rate of population decrease of the region, with a rate of 9.6% between 2006 and 2011. Forested areas and waterways dominate the land use of Bas-Saint-Laurent. The region counts of mixed forests, of coniferous forests and of waterways. Humid lands only covers and the land devoted to agriculture covers , while developed areas represent only , which equals to 0.5% of the total land area of the region. Geology Even if an isolated area of Cambrian and Precambrian rocks exist in an area of the Chic-Choc Mountains, the region belongs generally to the geologic province of the Appalachian Mountains, which covers an area of , between Alabama and Newfoundland. The marks of two episodes of mountain-building, the Acadian orogeny and the Taconic orogeny, have shaped the land. During the first orogeny, the subduction of the oceanic plate created a volcanic chain in the Iapetus Ocean, off the coast of Laurentia during the Cambrian period. The magma surfacing mixed with the sediments originating from the continental erosion and the volcanic arc of islands got gradually closer to the continent to the subduction. The two collided 450 million years ago and formed a chain of immature mountains, the Taconic Mountains, their nappe covers a part of the Saint Lawrence Lowlands. This first zone, which follows the river today, is known as Humber's zone. Dating from the Ordovician, this bedrock is composed primarily of sedimentary rocks : sandstone, mudrocks and conglomerates. South of this zone, the Gaspé belt is the remnant of a second mountain formation during Siluro-Devonian times. Around 430 million years ago, the Taconic mountains eroded and created sediments that deposited at a shallow depth. As Laurentia and the micro-continent Avalonia deformed and raised the sedimentary deposits and volcanic rocks and created a second chain of mountains, the Acadian Chain, which superposes itself on the Taconic Chain. Seismicity The estuary of the Saint Lawrence river in front of the Charlevoix region is one of the most active seismic regions in the east of Canada. Five earthquakes of a magnitude superior to 6 have occurred in history, in February 1663, December 1791, October 1860, October 1870 and February 1925. The distribution of these earthquakes indicates