ABSTRACT We present the first critical examination of the > 1300 yr history of the Borujerd old congregational mosque by means of scrutinizing ancient historical chronicles, archaeology, architecture, historical and modern seismicity, geology, and regional active faults. Our study resulted in recognition of at least four major phases of destruction, rebuilding, and renovations of the megastructure located 4 km to the northeast of the Zagros Main Recent fault in western Iran. The grand structure shows significant paleo-architectural and archaeological evidence of destruction and damage. Although some damage events, recorded in seven phases since the seventh century C.E., could have been due to the poor construction of early periods and their decay, there is strong evidence of at least one extensive, simultaneous, and abrupt destruction and damage pattern of mosque III (ca. post–1090/pre–1139 C.E.) in the early fourteenth century. We suggest that the poorly known 1316 C.E. strong earthquake (which destroyed more than 20 villages in the general area, with erroneous epicentral location in the historical seismic catalogues) was possibly responsible for the simultaneous sudden collapse of the Borujerd congregational mosque lofty dome chamber and its tall free-standing minaret; we infer that this earthquake occurred with intensity > VIII + (modified Mercalli intensity scale) conceivably along a seismic gap zone of the Zagros Main Recent fault. No pre–1316 C.E. monument exists in the epicentral region, and no strong earthquake has occurred along that segment of the Zāgros Main Recent fault for the last seven centuries. Retrospectively, apparent indigenous paleo-architectural renovations were utilized during construction of the new congregational mosque (mosque IV: ca. post–1405/pre–1447 C.E.) to enhance the coherency and elasticity of the rigid brick structure to withstand future earthquake shear stress. The hazard-reducing efforts included: (1) retrofitting the surviving load-bearing structural elements; (2) avoiding grandeur and majesty and implementing simplicity by reducing the size, height, and shape of the dome chamber; (3) avoiding free-standing minarets; (4) minimizing the size and reducing the light/ventilation openings; and (5) utilizing several levels of timber bracings to neutralize earthquake strong ground motion. Our research reveals that the return period of large-magnitude earthquakes along the two major segments of the fault is in the range of 1000 and 2000 yr, thus making historical earthquakes unrecognizable through routine historical research. It also shows how the use of archaeoseismology and paleo-architectural investigations on deformed monuments may improve our knowledge of long-term seismicity and seismic hazards of a region. This kind of study permits us to hypothesize the occurrence of strong earthquakes in an area for which historical seismicity does not show significant earthquakes. Finally, based on the described historic seismic damage and destruction, the regional national monuments should be properly retrofitted to withstand future earthquake hazards.

ABSTRACT This is an in-depth review and analysis of the long and untold history of development of earth science, geological thinking, research, and exploration on the Iranian Plateau within its historical, political, and socioeconomic context. Widespread mineral resources and ancient civilization helped in exploration, excavation, smelting, and usage of different metals, precious stones, and minerals since the Neolithic Period. Extant ancient Avestan and Middle Iranian Pahlavi Zoroastrian texts, as well as the classic Greek and Roman scholars, clearly demonstrate the Iranian geological activity through the Median (ca. 615 BCE), Achaemenid (550–330 BCE), Parthian (250 BCE–224 CE), and Sassanid (224–642 CE) Dynasties, interrupted by disrupting periods of socioeconomic and political problems, followed by foreign invasions and devastation in 330 BCE–250 CE and 637–652 CE, when the Iranians could no longer make scientific advancements. Long after the invasion of Alexander III of Macedon (330 BCE), scientific activity culminated in the establishment of the academies of Gundishāpur, Ctesiphon, and Resaina, the three higher educational centers of the Sassanid Dynasty that focused on comprehensive observation, painstaking research, and advanced education during the sixth and seventh centuries CE. Careful observation, research, and experiment by brilliant and genius scholars such as Karaji, Biruni, and Avicenna took place during a period of great activity and growth in science, engineering, medicine, literature, art, architecture, and philosophy in the tenth and eleventh centuries CE in Iran. This Iranian two-century “intermezzo intellectual zenith,” with a stable state and economic prosperity, was nurtured by the vast heritage of the ancient Iranian, Mesopotamian, Indian, and Egyptian civilizations and elements of the ancient Avestan, Sanskrit, and Pahlavi writings since ca. 1200 BCE. Social, economic, and political conflicts followed by invasions by Central Asian nomadic tribe warlords and their accompanying hordes in 1000–1040 CE (Saljuqs), 1218–1231 CE, and 1256 CE (Mongols), and 1370 CE (Timurids), and their occupation caused the process of irreversible decay, retrogression, and general intellectual decadence until the Safavids (1491–1772 CE). During this relatively long dark period, there was a drastic decline in interest in geological research and writing, though some old mining efforts were active. Throughout the eighteenth to the mid-twentieth centuries, foreign travelers made some contributions to the geology and mineral resources of Iran. It was during the second half of the twentieth century when once again earth science research blossomed in Iran with the help of European geologists. This ushered in a new period of modern geologic studies of Iran by native geologists. In memory of Emil Tietze (1845–1931), Alexander von Stahl (b. 1850), Setrāk Ābdāliān ( 1894–1963), Eugène Rieben (1899–1972), Heinrich Martin Huber (1917–1992), Jovan Stöcklin ( 1921–2008), Ricardo Assereto (1939–1976), and all pioneers in the past, who enthusiastically and rigorously intruded ever deeper into virtually unexplored territories in difficult and uncomfortable circumstances, extremely devoted to scientific pursuits, and shaped our understanding of the geology, tectonics, mineral resources, earthquakes, and seismotectonics of the Iranian Plateau .