Cycle 1 (2011 Deadline)
Discovering potential seismic sources in the Caucasus using virtual-reality based data analysis and development of a cyber-enabled geosciences workforce in Georgia
PI: Mikheil Elashvili, Ilia State University
U.S. Partner: Louise Kellogg, University of California Davis
Project Dates: June 2012 - May 2017
The UAV used by the team to survey and photograph the ancient city of Vardzia (photo courtesy of Dr. Elashvili).
In much of the developing world, including Georgia, active faults with the potential to produce devastating earthquakes have yet to be identified, as illustrated by the frequent occurrence of such events on previously unidentified faults. Discovering and characterizing these potential seismic sources is an essential first step towards increasing disaster resilience. In particular, planning for and managing the impact of earthquake disasters requires knowing the location and three-dimensional (3D) geometry of active faults that may rupture to produce an earthquake, as well as the type, magnitude, and frequency of ruptures they are likely to produce. This project aims to increase disaster resilience and thus promote sustainable development in Georgia by discovering potential seismic sources in the Caucasus through the use of new virtual-reality (VR) based methods of data analysis. In particular, these researchers will use the new virtual-globe application Crusta
to map active faults and folds based on their distinctive expression in the landscape. Using the application Visualizer
they will also determine the subsurface geometry of potential seismic sources by analyzing the 3D distribution of relocated earthquakes. They will subsequently test their VR-based observations by conducting pilot field studies of active faults near the capital city of Tbilisi to determine fault geometries and slip-directions, as well as preliminary slip rates and earthquake histories.
This project will enhance the skills of Georgian researchers and students through mentor-based education and research in collaboration with their U.S. partners. Faculty and students at Ilia State University will learn how to use the VR-based software tools by receiving training at KeckCAVES (the W.M. Keck Center for Active Visualization in the Earth Sciences) at the University of California, Davis. With this training, ISU faculty will incorporate advanced visualization tools in their undergraduate and graduate courses. The project should also facilitate disaster mitigation efforts by improving understanding of potential seismic sources in Georgia, an essential first step towards preparing for such events and reducing their possible impacts.
Summary of Recent Activities
|The ancient city of Vardzia photographed via drone (photo courtesy of Dr. Elashvili).|
In the 2015-2016 year, the team continued its investigation of active faults in Okami. Field work was carried out at the fault scarp near the Tbilisi-Gori highway, between the villages of Okami and Igoeti. This previously unknown fault was discovered by the project team in an area with terrain that is less folded and unseparated, thus outcrops in the region are very rare. Therefore, the team decided to use paleo-seismological trenching which involved the digging of two trenches. The first one was about 10 meters long in spot without tectonic dislocation and the second one was up the slope and measurably larger. The team was able to excavate intriguing soil layers in the trenches consisting of dark-brown topsoil, followed by a carbonate yellow sandy, clay-like layer, and finally a third layer of buried topsoil. In addition, the team identified a 3-4 meter long thrust fault in middle of this trench which cut through all soil layers, except the first. The PI hypothesizes that this thrust fault buried the third layer, after a strong earthquake or several minor earthquakes. Work will be continued in the fall of 2016, in close collaboration with Dr. Eric Cowgill from UC Davis.
The team also made progress towards constructing 3D models of the Bronze Age settlement Tells in the Kolkheti lowland. The area represents polygon of dramatic changes in the environment during the past millennia and the team was able to use drone mounted photography to create a digital elevation model. The images were geotagged with GPS coordinates and their elevation above sea level. To achieve high degree of precision, six Ground Control Points (GCP) on the site were used to ensure precise geo-referencing of the created model. Furthermore, to receive palaeogeographical data, several vibracorings were conducted at the crest, slopes and surroundings of the settlement mounds using an Atlas Copco coring device. The photogrammetric models of the settlement mound of Ergeta 1 show clearly the extent of the mound and how people changed the local topography in the Bronze Age.
Lastly, the team was able to Reconstruct the Paleo-Environment of the Shiraki plain and identify traces of natural catastrophes and their effect on the early state formations in the Southern Caucasus. The study area of the semi-arid Shiraqi plain in South-East Georgia is characterized with an annual precipitation of less than 600mm and is a standard open dry steppic landscape today. However, recent data collected using remote sensing and archaeological studies, shows that early humans lived in this area until a sudden and abrupt departure at the end of the Bronze or early Iron Ages. There are almost no settlements in the area which is devoid of water resources today. Selected sites were investigated in detail and Archaeo-Botanic and soil studies demonstrate that the region was covered by forests at one point. Hydro modelling shows possible existence of a well-developed water network including a shallow lake at the center of plane. Remote sensing data and recent archaeological excavations at Didnauri site provides clear evidence of early state formation, with favorable paleo-environmental conditions.