Results of historical seismological analysis of Tuvan folklore for seismic risk assessment of Tuva Republic

Historical seismology, as a synthetic scientific discipline that studies information about earthquakes in written and oral historical sources, has promising prospects for development in Tuva, as the region lies in a seismically active zone. Plenty of material for research can be found in folklore and toponymy of Tuva. This information will help solve several important problems, such as the territorial distribution of earthquakes, determining their maximum strength, possible repetition intervals, etc. The article presents an analysis of the first few cases of unravelling information about ancient earthquakes in Tuva found in published folklore and toponymic sources. The story of the Kogey-Syny (the Tuvan name of the Khan-Khuhei Range in Mongolia) tells about the disputes between the Tuvans and the Mongolians of the Tuvan Khan-Khuhei mountains, after which an earthquake occurred, and a tectonic rift appeared along the Khan-Khuhei Range. It was decided to draw the border along the line of this gap. Obviously, it was the Bolnai earthquake (July 23, 1905, magnitude 8.2 – 8.5). In the legend of Hun-Korbes (a mountain near the Kaachem system of active rifts), lovers jumped from a high cliff, then a noisy rockfall happened. It obviously refers to a landfall after the earthquake, which occurs here every 300-500 years. There are also myths about the origin of names of certain geographical areas. The authors studied the geographical names of Western Tuva to identify signs possibly associated with any catastrophic events in the area. Provided in the article is a list of the most interesting place names from "A Toponymic Dictionary of Tuva" by B. K. Ondar (2007). They reflect the catastrophic land-forming processes along the Sayano-Tuva rift. The examples here form only a small part of the huge folklore heritage, which can and should be used to identify and reconstruct the natural events of the past. For a more accurate interpretation of folklore data, detailed field works using the methods of paleo- and archaeoseismology is required

Seismic history of the Altai-Sayan region and the 2011-2012 earthquakes in Tuva

The Tuva earthquakes of 2011-2012, being the strongest in the history of seismic study in Tuva, attracted the attention of professionals and became the first well-studied seismic events in Tuva. The paper provides a general overview of seismic history of the Altai-Sayan region and a look at a particular seismogenic structure – the Kaakhem system of active faults), where the 2011-2012 earthquakes occurred. A reconstruction of the seismic history of Tuva can follow a number of paths – aside from paleoseismological methods, those of archeoseismology and historical seismology can be quite helpful. Legends and more specific information on ancient constructions’ collapse can provide some useful information on earthquake dates, as well as earth tremor mapping. To locate seismic foci of the earthquakes of the past and assess their parameters, we may recourse to dating their geological vestiges, written evidence and archaeoseismological study outcomes obtained by means of velocity destruction indicators set in ancient buildings. Our comparative analysis has shown that the events of 2011-2012 are "ordinary" events against the background of the most powerful seismic catastrophes of the 20th century in the Altai-Sayan region, as well as prehistoric palaeoearthquakes located in the Kaakhem fault zone