Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

D I S C U S S I O N A N D P E R S P E C T I V E S This work aims to track evidence of past earthquakes by using turbidite records from lakes, however, turbidites are triggered in many other processes rather than earthquakes. These processes can involve river floods, landslides, spontaneous slope failures, or earthquakes (Talling, 2014). The very limited number of affluents with a length that varies between 4 and 6 km, 5 m wide and 20 cm depth, together with the low relief around the lakes (Figure 2), render floods and landslides unlikely triggering mechanisms. This assumption is consistent with the very low sedimentation rates, ranging from 0.11 mm/yr at Sangiyn Dalai Lake up to 0.45 mm/ yr at Takhilt Lake. These sedimentation rates and bathymetry lines account for a gentle slope of the basins and low hydrodynamic activity in the lakes, which rule out spontaneous slope failures as a possible trigger mechanism. Hence, the turbidites identified from the three different lakes are most likely related to earthquake- triggered turbiditic currents. The strongest evidence should be the historical correlation with the 1905 Bulnay earthquake, which is likely observed in the XRF profiles from Oygon lake thanks to the preservation of recent laminations. However, the compositional signature of this event is not evident in Takhilt and Sangiyn Dalai Lake. The very low sedimentation rates of these lakes constrain the event to be in the uppermost centimeters of the sediment column, a zone that is highly susceptible to disturbance during the coring process. Yet, it is hoped to find contemporaneous signatures of previous undocumented large earthquakes in all three lakes. In this work and for the first time, we will show lake-sedimentary records of earthquake-triggered- turbidites around the Bulnay fault. Furthermore, many observations in lakes worldwide suggest that remobilized material or slope collapses are triggered when a certain ground acceleration is reached (Moernaut et al, 2014; Wilhelm et al 2016). Thus, we aim to constrain the local earthquake turbidite- triggering threshold for all three lakes. Our observations will be fundamental to better understand the earthquake behavior along slow-slip intracontinental active faults.