At 20:08,on September 18,2024,an M4.7 earthquake occurred along the Tanlu fault zone in the Feidong County of Hefei,Anhui Province.This earthquake is the largest event in the modern history of Hefei,which caused subst...At 20:08,on September 18,2024,an M4.7 earthquake occurred along the Tanlu fault zone in the Feidong County of Hefei,Anhui Province.This earthquake is the largest event in the modern history of Hefei,which caused substantial social impact.To reveal the seismogenic structure of the M4.7 Feidong earthquake sequence and assess seismic risks,we use data from both the permanent seismic network and a temporary dense nodal array deployed in the epicentral region prior to the mainshock for:(1)accurate location of the earthquake sequence and determination of the focal mechanisms;(2)obtaining the spatiotemporal distribution,b-value,and half-day occurrence frequency of the earthquake sequence.The Sentinel-1 satellite data are used to analyze the coseismic displacement.Additionally,velocity models from regional tomography and local high-resolution 2D active-and passive-source surveys across the Tanlu fault zone in the epicentral area are also used to reveal the detailed geometry of the seismogenic fault.The results indicate:(1)the M4.7 Feidong earthquake sequence is concentrated around 10.5 km in depth along a NW-dipping,subvertical fault which trends NE and is approximately 5 km in length;the focal mechanism solution also reveals that the fault hosting the mainshock is a subvertical strike-slip fault,driven by the regional compressional stress in ENE-WSW;the coseismic horizontal displacement on the surface caused by the M4.7 mainshock has a maximum value close to 1 mm;(2)the regional velocity model shows significant lateral variation in v_(S) in the source region,with the mainshock occurring in the area with higher velocity;high-resolution P-wave velocity structures obtained by full waveform inversion from active sources,and S-wave velocity structures from passive-source ambient noise tomography indicate that the mainshock occurred along the boundary between high-and low-velocity bodies,and the seismogenic fault dips NW;the deep seismic reflection profiling shows that the mainshock occurred within the Jurassic strata;(3)based on these results,we suggest the seismogenic fault for the M4.7 Feidong earthquake is either the Zhuding-Shimenshan fault,one of the major faults in the Tanlu fault zone,or a hidden fault to the east;the intersection of the NE-trending Tanlu fault zone and the WNW-trending Feizhong fault,along with significant velocity variations,likely create local stress concentrations which could have triggered the M4.7 Feidong earthquake sequence;(4)the strong aftershocks following the M4.7 Feidong mainshock did not further extend the fault rupture zone;the active period of the Zhuding-Shimenshan fault was the late Early Pleistocene to Middle Pleistocene,and the imaging results indicate that this fault does not cut through the shallow Feidong depression.In conjunction with the small coseismic rupture area,it is inferred that the probability of surface-rupturing earthquakes in the future is relatively low.展开更多
Determining the rupture directivity for small earthquakes is challenging due to the small source dimension and limited resolution of far-field observations.In recent years,the burst of near-source observations provide...Determining the rupture directivity for small earthquakes is challenging due to the small source dimension and limited resolution of far-field observations.In recent years,the burst of near-source observations provides great opportunities to study earthquake rupture.Here we present the rapid determination of the rupture directivity for the 2024 Feidong M4.7 earthquake using only one strong motion station located 4 km from the epicenter.We find that the polarization of S waves evolves during the rupture,indicating an azimuth change during the rupture propagation.Through comparing the data with the synthetic waveforms,we infer that the M4.7 event propagated dominantly to the southwest on the dextral Tanlu fault.Our inference is further validated through comparing the data with records at local stations for M3 earthquakes in the Feidong sequence.Our study highlights the superior application of near-source observations in earthquake source studies.展开更多
Weak water stability and lithium reactivity are two major stability issues of sulfide solid-state electrolytes(SSEs)for all-solid-state lithium metal batteries.Here,we report on nano-sized boron nitride(BN)-coated Li_...Weak water stability and lithium reactivity are two major stability issues of sulfide solid-state electrolytes(SSEs)for all-solid-state lithium metal batteries.Here,we report on nano-sized boron nitride(BN)-coated Li_(5.7)PS_(4.7)Cl_(1.3)(BN@LPSC1.3)sulfide SSE,which exhibits reduced H_(2)S emission and improved ionic conductivity retention after relative humidity 1.2%-1.5%ambient condition exposure.Furthermore,BN can partially react with lithium metal to create stable Li_(3)N,resulting in BN@LPSC1.3 showing reduced reactivity against lithium metal and a higher critical current density of 2.2mA/cm^(2).The Li/BN@LPSC/Li symmetrical battery also shows considerably greater stability for>2000 h at a current density of 0.1mA/cm^(2).Despite the high cathode mass loading of 13.38mg/cm^(2),the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/BN@LPSC1.3/Li all-solidstate lithium metal battery achieves 84.34%capacity retention even after 500 cycles at 0.1 C and room temperature(25℃).展开更多
A new single micro-particle electrode(SMPE)fabrication technique the inlaid SMPE technique was introduced in this paper.The preparation procedure of an alloy SMPE was described in detail.Based on the SMPE technique,th...A new single micro-particle electrode(SMPE)fabrication technique the inlaid SMPE technique was introduced in this paper.The preparation procedure of an alloy SMPE was described in detail.Based on the SMPE technique,the electrochemical behavior of LaNi_ 4.7Al_ 0.3 spherical particles with two different radii was investigated.The results of CV study showed that more detailed electrochemical information of the alloy can be provided on the alloy SMPE as compared with that on the composite alloy electrode.The results of potential step study depict that H diffusion coefficient in LaNi_ 4.7Al_ 0.3 keeps almost constant when the size of the alloy particle changes,and the diffusion coefficient measured on the alloy SMPE[(2.5—2.6)×10-9 cm 2/s] is about one order larger than that detected on the composite alloy electrode.展开更多
基金supported by the Anhui Province Science and Technology Breakthrough Plan Project(Key Project,No.202423l10050030)the National Natural Science Foundation of China(Fundamental Science Center Category B,No.4248830017)+4 种基金the Joint Funds of National Natural Science Foundation of China(No.U2139204)the National Natural Science Foundation of China Project(No.42104063)the Hefei Government Key Construction Project(No.2024BFFFD02048)the Earthquake Science and Technology Spark Program of the China Earthquake Administration(Nos.XH23020YA,XH24020B)the Anhui Mengcheng National Geophysical Observatory Joint Open Fund(No.MENGO-202307).
文摘At 20:08,on September 18,2024,an M4.7 earthquake occurred along the Tanlu fault zone in the Feidong County of Hefei,Anhui Province.This earthquake is the largest event in the modern history of Hefei,which caused substantial social impact.To reveal the seismogenic structure of the M4.7 Feidong earthquake sequence and assess seismic risks,we use data from both the permanent seismic network and a temporary dense nodal array deployed in the epicentral region prior to the mainshock for:(1)accurate location of the earthquake sequence and determination of the focal mechanisms;(2)obtaining the spatiotemporal distribution,b-value,and half-day occurrence frequency of the earthquake sequence.The Sentinel-1 satellite data are used to analyze the coseismic displacement.Additionally,velocity models from regional tomography and local high-resolution 2D active-and passive-source surveys across the Tanlu fault zone in the epicentral area are also used to reveal the detailed geometry of the seismogenic fault.The results indicate:(1)the M4.7 Feidong earthquake sequence is concentrated around 10.5 km in depth along a NW-dipping,subvertical fault which trends NE and is approximately 5 km in length;the focal mechanism solution also reveals that the fault hosting the mainshock is a subvertical strike-slip fault,driven by the regional compressional stress in ENE-WSW;the coseismic horizontal displacement on the surface caused by the M4.7 mainshock has a maximum value close to 1 mm;(2)the regional velocity model shows significant lateral variation in v_(S) in the source region,with the mainshock occurring in the area with higher velocity;high-resolution P-wave velocity structures obtained by full waveform inversion from active sources,and S-wave velocity structures from passive-source ambient noise tomography indicate that the mainshock occurred along the boundary between high-and low-velocity bodies,and the seismogenic fault dips NW;the deep seismic reflection profiling shows that the mainshock occurred within the Jurassic strata;(3)based on these results,we suggest the seismogenic fault for the M4.7 Feidong earthquake is either the Zhuding-Shimenshan fault,one of the major faults in the Tanlu fault zone,or a hidden fault to the east;the intersection of the NE-trending Tanlu fault zone and the WNW-trending Feizhong fault,along with significant velocity variations,likely create local stress concentrations which could have triggered the M4.7 Feidong earthquake sequence;(4)the strong aftershocks following the M4.7 Feidong mainshock did not further extend the fault rupture zone;the active period of the Zhuding-Shimenshan fault was the late Early Pleistocene to Middle Pleistocene,and the imaging results indicate that this fault does not cut through the shallow Feidong depression.In conjunction with the small coseismic rupture area,it is inferred that the probability of surface-rupturing earthquakes in the future is relatively low.
基金Suli Yao is partially supported by a Postdoc Fellowship from Faculty of Science,CUHK.Hongfeng Yang acknowledged the support from National Key R&D Program of China(No.2023YFF0803202)and HKSAR RGC(No.14308523)Zhigao Yang acknowledged the support from the Earthquake Spark Technology Project(No.XH23051B).
文摘Determining the rupture directivity for small earthquakes is challenging due to the small source dimension and limited resolution of far-field observations.In recent years,the burst of near-source observations provides great opportunities to study earthquake rupture.Here we present the rapid determination of the rupture directivity for the 2024 Feidong M4.7 earthquake using only one strong motion station located 4 km from the epicenter.We find that the polarization of S waves evolves during the rupture,indicating an azimuth change during the rupture propagation.Through comparing the data with the synthetic waveforms,we infer that the M4.7 event propagated dominantly to the southwest on the dextral Tanlu fault.Our inference is further validated through comparing the data with records at local stations for M3 earthquakes in the Feidong sequence.Our study highlights the superior application of near-source observations in earthquake source studies.
基金financial support from the Science and Technology Project of Shenzhen(Nos.JCYJ20210324094206019 and JCYJ20210324094000001).
文摘Weak water stability and lithium reactivity are two major stability issues of sulfide solid-state electrolytes(SSEs)for all-solid-state lithium metal batteries.Here,we report on nano-sized boron nitride(BN)-coated Li_(5.7)PS_(4.7)Cl_(1.3)(BN@LPSC1.3)sulfide SSE,which exhibits reduced H_(2)S emission and improved ionic conductivity retention after relative humidity 1.2%-1.5%ambient condition exposure.Furthermore,BN can partially react with lithium metal to create stable Li_(3)N,resulting in BN@LPSC1.3 showing reduced reactivity against lithium metal and a higher critical current density of 2.2mA/cm^(2).The Li/BN@LPSC/Li symmetrical battery also shows considerably greater stability for>2000 h at a current density of 0.1mA/cm^(2).Despite the high cathode mass loading of 13.38mg/cm^(2),the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/BN@LPSC1.3/Li all-solidstate lithium metal battery achieves 84.34%capacity retention even after 500 cycles at 0.1 C and room temperature(25℃).
文摘A new single micro-particle electrode(SMPE)fabrication technique the inlaid SMPE technique was introduced in this paper.The preparation procedure of an alloy SMPE was described in detail.Based on the SMPE technique,the electrochemical behavior of LaNi_ 4.7Al_ 0.3 spherical particles with two different radii was investigated.The results of CV study showed that more detailed electrochemical information of the alloy can be provided on the alloy SMPE as compared with that on the composite alloy electrode.The results of potential step study depict that H diffusion coefficient in LaNi_ 4.7Al_ 0.3 keeps almost constant when the size of the alloy particle changes,and the diffusion coefficient measured on the alloy SMPE[(2.5—2.6)×10-9 cm 2/s] is about one order larger than that detected on the composite alloy electrode.
