 It defined phases of occupation (see section below) that differ chronologically and in some technological and cultural aspects, but that are also, at their cores, remarkably similar given the numerous volcanic upheavals the area endured.Researchers found villages to have been occupied continuously from 2000 BC up until the centuries before the arrival of the Europeans, and stone tools to have been made the same way all throughout the recorded period of occupation.Compared to other Mesoamerican and Middle American populations, the Arenalan one was determined to have been incredibly self-sufficient (thanks in large part to the local availability of resources) and stable, having never experienced huge population increases or periods of dependence on a single agricultural staple.