A Preliminary Seismic Hazard Assessment of the Sakhalin-Mainland Area for a Critical Linear Structure

摘要

The results of seismic hazard zoning of the submerged crossing of the pipeline in the Nevelskoy Strait, between the village of Lazarev of the Nikolaevsky district, Khabarovsky krai, and Cape Pogibi near the village of Pogibi, Sakhalin oblast are presented. Along the water area, this section of the crossing is limited by a zone that is 500 m wide and 11 km long. It follows from the stock of geological documents of the Geophysical Service of the Russian Academy of Sciences and the general seismic zoning map (GSZ-2015) that the highest seismic activity in the Okhotsk region is observed in the area of the Kuril Islands, while the closest activity to the construction site manifests itself in the central zone of northern Sakhalin. Large earthquakes are recorded by a number of seismological stations in the immediate vicinity of the construction site. The foci of nearby earthquakes are displaced eastward of the construction site and are mostly confined to the systems of deep faults that result from the juncture between the West Sakhalin synclinorium and the Sikhote Alin volcanic belt. The main purpose of this research is related to the development of a procedure for forecasting seismic impacts for the areas that are prone to predicted strong earthquakes. In this context, an approach is proposed for the specific structure, which is based on the construction of a set of the most probable seismic models to reach the reference bedrock, setting of the pickup signal corresponding to initial seismicity of the area, calculating the main parameters of seismic impacts for them, and then, in the first approximation, the implementation of the technology for constructing an engineering-seismological cross-section along the pipeline construction site. The proposed approaches to forecasting seismic events for the section of the pipeline crossing in the Nevelskoy Strait are based on certain restrictions that made it possible to obtain a set of parameters of seismic impacts for predicted strong earthquakes that are necessary for design and construction of an earthquake-resistant linear structure. In improving the calculation methods and monitoring critically important objects, the advantage of this approach is the ability to recalculate seismic impacts on a structure using the constructed seismic ground-motion models.