ABSTRACT A brief history of seismotectonic studies in Armenia, especially after the 1988 Spitak earthquake, and new information on the active faults shed light on several key issues and areas of research in the country. Data are provided on the geometry, kinematics, and slip rates of several important active faults, including the Pambak-Sevan-Syunik fault system, and Garni, Akhouryan, Javakhq, Sizavet, and Akera faults, based on geological observations and global positioning system measurements. An updated map of active faults and a regional seismotectonic model of Armenia and adjacent countries are presented. Two cases studies are highlighted. The first concerns the question of the epicenter locations and magnitude assessments for the Dvin earthquakes of the ninth century CE. New evidence and reanalysis of earlier information indicate that serious damage of historical buildings and significant secondary soil deformations in the Garni fault zone occurred around the second part of the ninth century. This evidence questions the previous localization of the epicenters of the 863 and 893 CE events in the ancient Dvin city area. The Garni fault is located just 17 km north of Dvin, and strong earthquakes in its zone were quite capable of causing damage to that city. The second case examines active faults in the Lake Sevan basin, where pull-apart structures between the segments of the Pambak-Sevan-Syunik fault are identified on the lake floor. The length of these transtensional structures is from 11 to 15 km, and their widths vary between 5 and 7 km. Seismotectonic and geochemical activity of the faults on the lake floor gives a consistent picture. The faults in the basin and on the floor of Lake Sevan are oblique normal faults with a right-lateral strikeslip component, and they reflect an E-W extensional setting.

ABSTRACT The seismically active Pambak-Sevan-Syunik fault system is the largest of its kind in Armenia. During 2004–2012, archaeoseismological and paleoseismological studies were carried out along the southeastern segment of the active Pambak- Sevan-Syunik fault system (PSSF-3). These studies were conducted at six sites located within a 43-km-long section of the fault segment. Earthquake signs were studied on the northernmost site, in an ancient settlement dated to the Middle Bronze Age (the twenty-fourth to sixteenth centuries BCE). Offsets of barrows and walls dated to the Late Bronze–Early Iron Age (the twelfth to ninth centuries BCE) by surface ruptures were studied in some other localities of PSSF-3. Surface breaks caused by strong earthquakes were recorded at all the studied sites; some were observed to have caused 5.2 m to 8 m offsets of ancient structures by right-lateral strike-slip faulting. Radiocarbon dating of the earthquake that generated these surface breaks indicated that it occurred between the first and the fourth centuries CE. There is, indeed, historical evidence for a strong earthquake in the studied region dated to 368 CE. Signs of even older earthquakes were identified in two places in the excavated old structures and in paleoseismological trenches, and these were related to the Middle Bronze Age. The new data and discussion enable reestimation of the seismic hazard and slip rates for the southeastern segment of the Pambak-Sevan-Syunik fault system.

Our studies in the temple of Amenhotep III, conducted under the project on Excavation and Conservation at Kom el-Hettan, provide new information about the seismic history of ancient Thebes. Distinct signs of liquefaction are revealed at the temple site. Trenches exhibit sand dikes and sills that formed extension cracks through the mechanism of lateral spreading. Clear effects of liquefaction by lateral spreading were discovered in other monuments on the west bank of the Nile. Application of historical, archaeological, and geological methods enables us to constrain the time of the earthquake responsible for the damage in the west bank temples to between 1200 and 901 B.C. Furthermore, we find no signs of an earthquake in 27 B.C. The foot of the Thebes Plateau may conceal a basement fault with combined vertical and horizontal slip kinematics. The fault located to the southeast, near an ancient sanctuary, may correspond to either seismogenic fault surface rupture, or a secondary seismic effect manifested as subordinate rupture and ground failure.