Velocity structure in the South Yellow Sea basin based on first-arrival tomography of wide-angle seismic data and its geological implications

The South Yellow Sea basin is filled with Mesozoic-Cenozoic continental sediments overlying pre-Palaeozoic and Mesozoic-Palaeozoic marine sediments.Conventional multi-channel seismic data cannot describe the velocity structure of the marine residual basin in detail,leading to the lack of a deeper understanding of the distribution and lithology owing to strong energy shielding on the top interface of marine sediments.In this study,we present seismic tomography data from ocean bottom seismographs that describe the NEE-trending velocity distributions of the basin.The results indicate that strong velocity variations occur at shallow crustal levels.Horizontal velocity bodies show good correlation with surface geological features,and multi-layer features exist in the vertical velocity framework(depth:0–10 km).The analyses of the velocity model,gravity data,magnetic data,multichannel seismic profiles,and drilling data showed that high-velocity anomalies(>6.5 km/s)of small(thickness:1–2 km)and large(thickness:>5 km)scales were caused by igneous complexes in the multi-layer structure,which were active during the Palaeogene.Possible locations of good Mesozoic and Palaeozoic marine strata are limited to the Central Uplift and the western part of the Northern Depression along the wide-angle ocean bottom seismograph array.Following the Indosinian movement,a strong compression existed in the Northern Depression during the extensional phase that caused the formation of folds in the middle of the survey line.This study is useful for reconstructing the regional tectonic evolution and delineating the distribution of the marine residual basin in the South Yellow Sea basin.

Tectonic implications of the subduction of the Kyushu-Palau Ridge beneath the Kyushu,southwest Japan

The Kyushu-Palau Ridge(KPR),a remnant arc on the Philippine Sea Plate(PSP),is subducting beneath the Kyushu,southwest Japan.Influenced by the subducting KPR,the Kyushu subduction zone corresponding to the KPR is significantly different from Shikoku subduction zone in terms of gravity anomalies,seismicity,the stress state,and the subducting slab morphology.Significant negative free-air and Bouguer gravity anomalies are observed in a prolonged area of KPR,southeast of the Miyazaki Plain,indicating that this is where KPR overlaps the overriding plate.The gravity anomaly in this area is much lower than that in other areas where the inferred KPR extends,suggesting that the subduction of the buoyant KPR may cause the lower mantle density to decrease.More earthquakes have occurred in Hyuga-nada region where the KPR subducts than in Shikoku forearc and other areas in the Kyushu forearc,indicating that the subduction of the KPR enhances the local coupling between the subducting and overriding plates.The centroid moment tensor(CMT)mechanism of earthquakes shows that stress is concentrated in the accumulated crust beneath the Kyushu forearc corresponding to the KPR,and the shallow thrusting events in the obducting plate are caused by the KPR subduction.The buoyant KPR,with a large volume of low-density sediments,was responsible for the differences of the subduction depth and dip angle of the subducting Philippine Sea(PS)slab between northern Kyushu and Shikoku.The seismic gaps and the sudden change of the dipping angle of the subducting PS slab indicate that slab tear may have occurred along the west side of the KPR beneath southwest Kyushu.A two-tear model was proposed,and the subduction of the buoyant KPR was believed to play an important role in the slab tear.

Cross-talking between autophagy and viral infection in mammalian cells

Autophagy is a cellular process in degradation of long-lived proteins and organelles in the cytosol for maintaining cellular homeostasis,which has been linked to a wide range of human health and disease states,including viral infection.The viral infected cells exhibit a compli-cated cross-talking between autophagy and virus.It has been shown that autophagy interacts with both adaptive and innate immunity.For adaptive immunity,viral antigens can be processed in autophagosomes by acidic proteases before major histocompatibility complex(MHC)class II presentation.For innate immunity,autophagy may assist in the delivery of viral nucleic acids to endosomal TLRs and also functions as a part of the TLR-or-PKR-downstream responses.Autophagy was also reported to suppress the magnitude of host innate antiviral immunity in certain cases.On the other hand,viruses has evolved many strategies to combat or utilize the host autophagy for their own benefit.In this review we discussed recent advances toward clarifying the cross-talking between autophagy and viral infection in mammalian cells.