Geomorphologic features usually associated with the alluvial stretches of mature rivers, comparable to meanders, oxbow lakes, lower-offs, and intensive floodplains are restricted to a short stretch of the mainstream round Vientiane and downstream of Kratie the place the river develops alluvial channels which can be free of control exerted by the underlying bedrock. The Mekong basin shouldn't be usually thought-about a seismically active area as much of the basin is underlain by the relatively stable continental block. Nonetheless, the parts of the basin in northern Laos, northern Thailand, Myanmar and China do expertise frequent earthquakes and tremors. The magnitude of those earthquakes hardly ever exceeds 6.5 on the Richter magnitude scale and is unlikely to cause material harm. The issue of navigating the river has meant that it has divided, somewhat than united, the people who reside near it. The earliest identified settlements date to 210 BCE, with Ban Chiang being a superb instance of early Iron Age tradition. The earliest recorded civilization was the first century Indianised-Khmer culture of Funan, in the Mekong delta. Excavations at Oc Eo, close to trendy An Giang, have found coins from as far away because the Roman Empire. This was succeeded by the Khmer tradition Chenla state around the fifth century. The Khmer empire of Angkor was the last great Indianized state within the region. From across the time of the fall of the Khmer empire, the Mekong was the entrance line between the emergent states of Siam and Tonkin (North Vietnam), with Laos and Cambodia, then on the coast, torn between their influence.