The 2010 Mw 6.9 Yushu earthquake produced a ~33-km-long co-seismic surface rupture zone along the pre-existing active Yushu Fault on China’s central Tibetan Plateau. Sand boils occurred along the tension cracks of th...The 2010 Mw 6.9 Yushu earthquake produced a ~33-km-long co-seismic surface rupture zone along the pre-existing active Yushu Fault on China’s central Tibetan Plateau. Sand boils occurred along the tension cracks of the co-seismic surface rupture zone, and locally spouted up above the ground to coat the top of limestone blocks that had slid down from an adjacent ~300-m-high mountain slope. Based on our observations, the relations between the arrival times of P- and S-waves at the sand-boil location and the seismic rupture velocity, we conclude that 1) the sand boils occurred at least 18.24 s after the main shock;2) it took at least 4.09 - 9.79 s after the formation of co-seismic surface rupture to generate liquefaction at the sand-boil location;3) the spouting height of sand boils was at least 65 cm. Our findings help to clarify the relationships between the timing of lique-faction and the spouting height of sand boils during a large-magnitude earthquake.展开更多
In May 2012,the Emilia region of the Po Valley was struck by a seismic crisis with two major events of magnitude M_w 6.1and M_w 5.9.The first event induced widespread sand blows formed along buried channels and old cr...In May 2012,the Emilia region of the Po Valley was struck by a seismic crisis with two major events of magnitude M_w 6.1and M_w 5.9.The first event induced widespread sand blows formed along buried channels and old crevasse splay deposits.In the days immediately following the events,the detailed mapping and sampling of the erupted sand was fundamental to record all the seismically-induced phenomena.The study of a trench dug across large fractures at San Carlo(Ferrara)provided also valuable information on the sand blows mechanism and regome.The sedimentological and compositional characteristics of the fracture-filling materials indicate that the sands were erupted from a layer located between 6.8 and 7.5 m depth.Older and deeper Holocene and Pleistocene sand layers were not apparently involved in the liquefaction phenomena.展开更多
文摘The 2010 Mw 6.9 Yushu earthquake produced a ~33-km-long co-seismic surface rupture zone along the pre-existing active Yushu Fault on China’s central Tibetan Plateau. Sand boils occurred along the tension cracks of the co-seismic surface rupture zone, and locally spouted up above the ground to coat the top of limestone blocks that had slid down from an adjacent ~300-m-high mountain slope. Based on our observations, the relations between the arrival times of P- and S-waves at the sand-boil location and the seismic rupture velocity, we conclude that 1) the sand boils occurred at least 18.24 s after the main shock;2) it took at least 4.09 - 9.79 s after the formation of co-seismic surface rupture to generate liquefaction at the sand-boil location;3) the spouting height of sand boils was at least 65 cm. Our findings help to clarify the relationships between the timing of lique-faction and the spouting height of sand boils during a large-magnitude earthquake.
文摘In May 2012,the Emilia region of the Po Valley was struck by a seismic crisis with two major events of magnitude M_w 6.1and M_w 5.9.The first event induced widespread sand blows formed along buried channels and old crevasse splay deposits.In the days immediately following the events,the detailed mapping and sampling of the erupted sand was fundamental to record all the seismically-induced phenomena.The study of a trench dug across large fractures at San Carlo(Ferrara)provided also valuable information on the sand blows mechanism and regome.The sedimentological and compositional characteristics of the fracture-filling materials indicate that the sands were erupted from a layer located between 6.8 and 7.5 m depth.Older and deeper Holocene and Pleistocene sand layers were not apparently involved in the liquefaction phenomena.
