Drawing on a broad range or sources, including folkloric, mythical, religious, literary, and scientific materials, the author investigates various beliefs and ideas about earthquake in the highly-seismic Iranian Plateau. The set of Persian beliefs that attributes the cause of earthquake to either subterranean creatures or the divine will is compared to those among other nations. Interesting ideas about earthquake are found in the Zoroastrian apocalyptic literature, where, along with Ahrīman, the demon casmag, "well" or "spring", is thought to be the shaker of the earth. While it is hard to establish a lexical association between spring and seism, the former is indeed a natural cause of the latter, yet any further postulation should be supported by extra evidence. Aside from the views that are categorized as superstition by today's scientific standards, there were also those with various degrees of insightfulness and sophistication about the cause of earthquakes. The most comprehensive arguments of this type among Muslims are found in Avicenna's Atār al-olwī_yya, which adopts the Aristotelian theory of "subterranean wind pressure" documented in Meteorologica, yet, as the author argues, not without an important extension: the vibrant gases escape upward where deep wells are dug into the ~round; hence the chances of earthquake diminish. We find a fusion of the Aristotelian theory and popular beliefs in the Pahlavi Bundahishn and then in-the Persian popular genre AJa'eb al-magluqat, with striking similarity between them. Subsequently, there were such Persian scholars as Biruni and Karaji who commented on what we now call hydro-seismology. Another medieval source implies Tsunami attacks on southwestern Caspian shores. Remarkable conclusions can be drawn by comparing the geotectonic of Eurasia and the oldest layers of Indo-Iranian mythology. Lack of mention of earthquake in the latter sources accords with the low seismiscity of the Kazakh Steppe and the South Siberia - the supposed homeland of th proto-Aryans. Seismic geography is further extended by the author to the hypothetical homeland of the proto-Indo-Europeans on the one hand and to the successive southward migrations of Iranian-speaking tribes in central Asia on the other.