15:30 〜 16:30
[S07-P-15] Surface deformations caused by underground nuclear explosions
We observed surface deformations at several sites within alluvial plain in the Semipalatinsk testing area. Field research included geomorphological observations and topogeodesic leveling along profiles with the length of 1,5-3 km. Technogenic forms of relief include:
-intensive ground loosening,
-ground swelling of amplitude from 0.5 to 1.0 m, length up to 20 m,
-local depression with a radies of 2 to 10 m, 0.5-0.7 m depth and
-ground fractures with a length of the first meters to 20 m and opening of 3-4 cm, rarely 10 cm.
We analyzed data that were carried on 20 objects before and after explosion and established that explosion caused deformation amplitude relates to the vertical peak ground velocity as a power function. Deformation area has a radius of 0.5 to 1.5 km. It is interesting that point of maximum deformation is displaced from the burst epicenter to the distance of 100-400 m.
The zonality of surface deformation corresponds to anthropogenic massif change due to the experiment and depends on massif lithologic-facial structure and physical-mechanical properties, underground water level, faults existence and paleorelief. In case of sedimentary and clastic rocks deformation area is asymmetric and corresponds to stratum attitude conditions. In tuffs it is usually uniform with the center at burst epicenter. In case of an explosion within shale and aleurolite massifs an elliptic cone is being formed along rock strike.
Shallow underground waters result increase of explosion impact on surface deformation. Maximum ground elevation without rupturing forms along the slope from terrace to flat due to soil displacement.
Large-scale experiments consequences corresponds to real post-seismic processes that were found out after earthquakes.
Described results are useful both for forecasting of areas of expected landslip processes and estimation of location and magnitude of historical earthquakes.
This work was supported by the Russian Science Foundation (Project No. 16-17-00095)
-intensive ground loosening,
-ground swelling of amplitude from 0.5 to 1.0 m, length up to 20 m,
-local depression with a radies of 2 to 10 m, 0.5-0.7 m depth and
-ground fractures with a length of the first meters to 20 m and opening of 3-4 cm, rarely 10 cm.
We analyzed data that were carried on 20 objects before and after explosion and established that explosion caused deformation amplitude relates to the vertical peak ground velocity as a power function. Deformation area has a radius of 0.5 to 1.5 km. It is interesting that point of maximum deformation is displaced from the burst epicenter to the distance of 100-400 m.
The zonality of surface deformation corresponds to anthropogenic massif change due to the experiment and depends on massif lithologic-facial structure and physical-mechanical properties, underground water level, faults existence and paleorelief. In case of sedimentary and clastic rocks deformation area is asymmetric and corresponds to stratum attitude conditions. In tuffs it is usually uniform with the center at burst epicenter. In case of an explosion within shale and aleurolite massifs an elliptic cone is being formed along rock strike.
Shallow underground waters result increase of explosion impact on surface deformation. Maximum ground elevation without rupturing forms along the slope from terrace to flat due to soil displacement.
Large-scale experiments consequences corresponds to real post-seismic processes that were found out after earthquakes.
Described results are useful both for forecasting of areas of expected landslip processes and estimation of location and magnitude of historical earthquakes.
This work was supported by the Russian Science Foundation (Project No. 16-17-00095)