Transient postseismic slip and aftershock triggering:A case study of the 2008 M_W7.9 Wenchuan Earthquake,China

In this study,we investigate how a stress variation generated by a fault that experiences transient postseismic slip(TPS)affects the rate of aftershocks.First,we show that the postseismic slip from Rubin-Ampuero model is a TPS that can occur on the main fault with a velocity-weakening frictional motion,that the resultant slip function is similar to the generalized Jeffreys-Lomnitz creep law,and that the TPS can be explained by a continuous creep process undergoing reloading.Second,we obtain an approximate solution based on the Helmstetter-Shaw seismicity model relating the rate of aftershocks to such TPS.For the Wenchuan sequence,we perform a numerical fitting of the cumulative number of aftershocks using the Modified Omori Law(MOL),the Dieterich model,and the specific TPS model.The fitting curves indicate that the data can be better explained by the TPS model with a B/A ratio of approximately 1.12,where A and B are the parameters in the rate-and state-dependent friction law respectively.Moreover,the p and c that appear in the MOL can be interpreted by the B/A and the critical slip distance,respectively.Because the B/A ratio in the current model is always larger than 1,the model could become a possible candidate to explain aftershock rate commonly decay as a power law with a p-value larger than 1.Finally,the influence of the background seismicity rate r on parameters is studied;the results show that except for the apparent aftershock duration,other parameters are insensitive to r.

Rapid report of the 8 January 2022 M_(S)6.9 Menyuan earthquake,Qinghai,China

The M_(S)6.9 Menyuan earthquake in Qinghai Province,west China is the largest earthquake by far in 2022.The earthquake occurs in a tectonically active region,with a background b-value of 0.87 within 100 km of the epicenter that we derived from the unified catalog produced by China Earthquake Networks Center since late 2008.Field surveys have revealed surface ruptures extending 22 km along strike,with a maximum ground displacement of 2.1 m.We construct a finite fault model with constraints from In SAR observations,which showed multiple fault segments during the Menyuan earthquake.The major slip asperity is confined within 10 km at depth,with the maximum slip of 3.5 m.Near real-time back-projection results of coseismic radiation indicate a northwest propagating rupture that lasted for~10 s.Intensity estimates from the back-projection results show up to a Mercalli scale of IX near the ruptured area,consistent with instrumental measurements and the observations from the field surveys.Aftershock locations(up to January 21,2022)exhibit two segments,extending to~20 km in depth.The largest one reaches M_(S)5.3,locating near the eastern end of the aftershock zone.Although the location and the approximate magnitude of the mainshock had been indicated by previous studies based on paleoearthquake records and seismic gap,as well as estimated stressing rate on faults,significant surfacebreaching rupture leads to severe damage of the high-speed railway system,which poses a challenge in accurately assessing earthquake hazards and risks,and thus demands further investigations of the rupture behaviors for crustal earthquakes.

A summary of seismic activities in and around China in 2021

In this article,we review the general characteristics of seismicity in and around China and the overall statistics of earthquake damage in 2021,focusing on several significant events and related scientific topics.Among them,the largest event is the M_(S)7.4 Madoi earthquake in Qinghai Province,northwest China.The event marks another M_(S)≥7 earthquake occurring near the boundary of the Bayan Har Block that has ended a remarkable quiescence of the M_(S)≥7 earthquakes within the Chinese mainland.In addition,the M_(S)6.4 Yangbi earthquake in Yunnan Province,southwest China draws the most attention because of its abundant foreshocks,which are well recorded by the densely distributed seismic stations in the surrounding regions.Regarding this event,we review several recent publications focusing on the Gutenberg-Richter b-value change and the physical mechanism of foreshocks associated with this sequence.The M_(S)6.0 Luxian earthquake in Sichuan Province,southwest China has caused serious damage with a relatively low magnitude,partly because the focal depth of the mainshock is relatively shallow (3.5 km).It is another strong earthquake occurring within the southeast Sichuan basin with low historical seismicity yet has increased significantly since 2015,probably due to shale gas development and associated hydraulic fracturing.

SKA2/FAM33A:A novel gene implicated in cell cycle,tumorigenesis,and psychiatric disorders

SKA2(spindle and KT associated 2),also referred to as FAM33A(family with sequence similarity 33,member A),is a recently identified gene involved in cell cycle regulation,and growing evidence is implicating its roles in tumorigenesis and psychiatric disorders.It has been demonstrated that SKA2,along with its coworkers SKA1 and SKA3,constitutes the SKA complex which plays a critical role in the maintenance of the metaphase plate and/or spindle checkpoint silencing during mitosis.SKA2 is over-expressed both in cancer cell lines and clinical samples including small cell lung cancer and breast cancer,whereas downregulation of SKA2 is associated with depression and suicidal ideation.The expression of SKA2 is regulated by transcription factors including NF-kB and CREB,miRNAs as well as DNA methylation.In this review,we provide an overview of studies that reveal SKA2 gene and protein characteristics as well as physiological function,with a special focus on its transcription regulatory mechanisms,and also provide a summary regarding the translational opportunity of the SKA2 gene as a clinical biomarker for cancers and psychiatric disorders.

LncRNAs LCETRL3 and LCETRL4 at chromosome 4q12 diminish EGFR-TKIs efficiency in NSCLC through stabilizing TDP43 and EIF2S1

Epidermal growth factor receptor(EGFR)-tyrosine kinase inhibitors(TKIs)are effective targeted therapy drugs for advanced nonsmall cell lung cancer(NSCLC)patients carrying sensitized EGFR mutations.The rapid development of EGFR-TKIs resistance represents a major clinical challenge for managing NSCLC.The chromosome 4q12 is the first genome-wide association study(GWAS)-reported locus associated with progression-free survival(PFS)of NSCLC patients treated with EGFR-TKIs.However,the biological significance of the noncoding transcripts at 4q12 in NSCLC remains elusive.In the present study,we identified two 4q12 long noncoding RNAs(lncRNAs)LCETRL3 and LCETRL4 which could significantly dimmish EGFR-TKIs efficiency.In line with their oncogenic role,evidently higher LCETRL3 and LCETRL4 levels were observed in NSCLC tissues as compared with normal specimens.Importantly,lncRNA LCETRL3 can interact with oncoprotein TDP43 and inhibit ubiquitination and degradation of TDP43.Similarly,lncRNA LCETRL4 can bind and stabilize oncoprotein EIF2S1 through reducing ubiquitin-proteasome degradation of EIF2S1.In particular,elevated levels of LCETRL3 or LCETRL4 in NSCLC cells resulted in stabilization of TDP43 or EIF2S1,increased levels of NOTCH1 or phosphorylated PDK1,activated AKT signaling and,thus,EGFR-TKIs resistance.Taken together,our data revealed a novel model that integrates two lncRNAs transcribed from the 4q12 locus into the regulation of EGFR-TKIs resistance in NSCLC.These findings shed new light on the importance of functionally annotating lncRNAs in the GWAS loci and provided insights to declare novel druggable targets,i.e.,lncRNAs,which may unlock the therapeutic potential of EGFR-TKIs resistant NSCLC in the clinic.