Journal of Geophysical Research: Solid Earth最新文献

{"title":"Influence of Normal Stress, Shear Velocity and Materials on Steady-State Shear Resistance and Viscosity of Rapid Dry Granular Flows","authors":"Wei Hu,&nbsp;Yan Li,&nbsp;Huaixiao Gou,&nbsp;Xiaoping Jia,&nbsp;Li Zhou,&nbsp;Chingshung Chang","doi":"10.1029/2025JB031305","DOIUrl":"https://doi.org/10.1029/2025JB031305","url":null,"abstract":"<p>Understanding the rheological behavior of rapid granular flows is crucial for understanding various geological processes, such as fast fault slip and rapid motion of landslides. In this study, we conducted rotary shear experiments on different granular materials, spanning a range of shear velocities from slow to rapid and under varying normal stresses, to investigate the evolution of mechanical behavior under different flow conditions. The experimental results showed that steady-state shear resistance varied with normal stress and material composition at shear velocities below 1 m/s. A consistent velocity-dependent trend was observed. The steady-state shear resistance of the sample experienced a transition from velocity-strengthening behavior at low shear velocities (below 0.1 m/s) to velocity-weakening behavior at higher shear velocities (above 0.1 m/s). Interestingly, at shear velocities exceeding 1 m/s, the steady-state shear resistance became independent of normal stress and material composition, converging to a similar steady-state value for both crushable and uncrushable materials. Although normal stress and mineral composition had a limited influence on steady-state shear resistance at high shear rates, they significantly affected the weakening rate (the transition from peak strength to steady-state shear resistance), which was strongly correlated with the material's crushing ability, as characterized by the Weibull modulus. These findings provide insights into the mechanisms governing the hypermobility of mega-landslides and the rapid dynamics of geological flows.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transient and Steady-State Dislocation Creep of Olivine Controlled by Dislocation Interactions at the Isostress Endmember","authors":"David Wallis,&nbsp;Thomas Breithaupt,&nbsp;Taco Broerse","doi":"10.1029/2024JB030606","DOIUrl":"https://doi.org/10.1029/2024JB030606","url":null,"abstract":"<p>The rheological behavior of olivine deforming by dislocation creep controls geodynamic processes that involve steady-state flow or transient viscosity evolution. Longstanding rheological models applied to both contexts assume that dislocation creep of olivine aggregates occurs close to the isostrain endmember with each grain deforming to the same strain but supporting different stress. Here, we test this assumption by constructing isostrain and isostress models based on flow laws for single crystals and comparing them to rheological data from aggregates. This analysis reveals that strain rates measured on olivine aggregates agree with those predicted by the isostress model but are an order of magnitude faster than those predicted by the isostrain model. When extrapolated to conditions typical of the shallow upper mantle, the isostress model predicts steady-state viscosities that are one to three orders of magnitude less than those predicted by the isostrain model. Furthermore, deformation close to the isostress endmember implies that transient creep occurs predominantly by dislocation interactions, suggesting viscosity changes that are approximately one order of magnitude greater than those predicted previously based on grain interactions associated with the isostrain model.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030606","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shallow Fault Zone Structure Affects Rupture Dynamics and Ground Motions of the 2019 Ridgecrest Sequence to Regional Distances","authors":"Nico Schliwa,&nbsp;Alice-Agnes Gabriel,&nbsp;Yehuda Ben-Zion","doi":"10.1029/2025JB031194","DOIUrl":"https://doi.org/10.1029/2025JB031194","url":null,"abstract":"<p>Seismic faults are surrounded by damaged rocks with reduced rigidity and enhanced attenuation. These damaged fault zone structures can amplify seismic waves and affect earthquake dynamics, yet they are typically omitted in physics-based regional ground motion simulations. We report on the significant effects of a shallow, flower-shaped fault zone in foreshock-mainshock 3D dynamic rupture models of the 2019 Ridgecrest earthquake sequence. We find that the fault zone structure both amplifies and reduces ground motions not only locally but at distances exceeding 100 km. This impact on ground motions is frequency- and magnitude-dependent, particularly affecting higher frequency ground motions from the foreshock because its corner frequency is closer to the fault zone's fundamental eigenfrequency. Within the fault zone, the shallow transition to a velocity-strengthening frictional regime leads to a depth-dependent peak slip rate increase of up to 70% and confines fault zone-induced supershear transitions mostly to the fault zone's velocity-weakening roots. However, the interplay of fault zone waves, free surface reflections, and rupture directivity can generate localized supershear rupture, even in narrow velocity-strengthening regions, which are typically thought to inhibit supershear rupture. This study demonstrates that shallow fault zone structures may significantly affect intermediate- and far-field ground motions and cause localized supershear rupture penetrating into velocity-strengthening regions, with important implications for seismic hazard assessment.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB031194","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-Time Delays in Induced Earthquakes Caused by Low-Permeability Bodies: Insights From the Xinfengjiang Reservoir, China","authors":"Lipeng He,&nbsp;Zhen Guo,&nbsp;Bin Luo,&nbsp;Qipeng Bai,&nbsp;Guangyao Yin,&nbsp;Keyuan Wu,&nbsp;Abayomi Gaius Osotuyi,&nbsp;Liwei Wang","doi":"10.1029/2024JB030579","DOIUrl":"10.1029/2024JB030579","url":null,"abstract":"<p>In many cases of induced seismicity, earthquakes occur significantly delayed to the initiation of industrial activities, yet the mechanisms behind these long-time delays remain poorly understood. In the Xinfengjiang Reservoir, an earthquake swarm became active in 2010, nearly 50 years after the initial impoundment in 1959. In this study, we conducted high-resolution 3D velocity tomography and focal mechanism analysis using a dense local seismic network. High-resolution seismic imaging identifies two downward migration channels enabling fluids to infiltrate the bedrock and low Vp/Vs anomalies at 5–10 km corresponding to low-permeability granitic bodies. Numerical simulations indicate that these Vp/Vs anomalies can delay pore-pressure diffusion by decades, resulting in delayed triggering of seismic events in the northwest of the reservoir. Our findings highlight the critical influence of low-permeability bodies in controlling the spatial-temporal evolution of reservoir-induced earthquakes and underscore the need to reconsider long-term seismic risk assessments for reservoirs situated in similar geological settings.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144312064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revisiting Seismicity Criticality: A New Framework for Bias Correction of Statistical Seismology Model Calibrations","authors":"Jiawei Li,&nbsp;Didier Sornette,&nbsp;Zhongliang Wu,&nbsp;Jiancang Zhuang,&nbsp;Changsheng Jiang","doi":"10.1029/2024JB029337","DOIUrl":"10.1029/2024JB029337","url":null,"abstract":"<p>The Epidemic-Type Aftershock Sequences (ETAS) model and its variants effectively capture the space-time clustering of seismicity, setting the standard for earthquake forecasting. Accurate unbiased ETAS calibration is thus crucial. But we identify three sources of bias, (a) boundary effects, (b) finite-size effects, and (c) censorship, which are often overlooked or misinterpreted, causing errors in seismic analysis and predictions. By employing an ETAS model variant with variable spatial background rates, we propose a method to correct for these biases, focusing on the branching ratio <i>n</i>, a key indicator of earthquake triggering potential. Our approach quantifies the variation in the apparent branching ratio (<i>n</i>_app) with increased cut-off magnitude (<i>M</i>_co) above the optimal cut-off (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msubsup>\u0000 <mi>M</mi>\u0000 <mtext>co</mtext>\u0000 <mtext>best</mtext>\u0000 </msubsup>\u0000 </mrow>\u0000 <annotation> ${M}_{text{co}}^{text{best}}$</annotation>\u0000 </semantics></math>), which is considered the best threshold for balancing catalog completeness and the amount of available data. The <i>n</i>_app(<i>M</i>_co) function yields insights superior to traditional point estimates. We validate our method using synthetic earthquake catalogs, accurately recovering the true branching ratio (<i>n</i>_true) after correcting biases with <i>n</i>_app(<i>M</i>_co). Additionally, our method introduces a refined estimation of the minimum triggering magnitude (<i>m</i>₀), a crucial parameter in the ETAS model. Applying our framework to the earthquake catalogs of California, New Zealand, the China Seismic Experimental Site in Sichuan and Yunnan provinces, and Noto Peninsula in Japan, we find that seismicity hovers away from the critical point, <i>n</i>_c = 1, remaining distinctly subcritical, however with values tending to be larger than recent reports that do not consider the above biases. Understanding seismicity's critical state significantly enhances our comprehension of seismic patterns, aftershock predictability, and informs earthquake risk mitigation and management strategies.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144312065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the Characteristics of Microseisms Using the Australian Seismic Arrays","authors":"Abhay Pandey,&nbsp;Hrvoje Tkalčić,&nbsp;Xiaolong Ma","doi":"10.1029/2024JB031032","DOIUrl":"https://doi.org/10.1029/2024JB031032","url":null,"abstract":"<p>Earth's microseisms are continuously recorded by seismographs worldwide. Yet, studies using broadband data to analyze microseisms in Australia have been rare. Building on initial research efforts that relied on the Warramunga array in the continent's center, we expand the investigation of microseisms by utilizing seismic arrays in various locations with distinct apertures and geometries, particularly spiral-arm arrays. Motivated by expanding knowledge of short-period microseisms, which are less studied than the peak of secondary microseisms, we investigate their distribution and characteristics. We process 1-year continuous waveform data using beamforming at various periods. Using the back-projection method, we then investigate the source areas of surface waves and teleseismic P waves generated by ocean activities. We also examine the seasonal variability of microseismic sources and their relationship with the ocean wave hindcast model by comparing our observations of Rayleigh (Rg) waves with modeled Rg wave sources and juxtaposing back-projected P-waves with significant wave heights and modeled P-wave sources. Our results suggest that over interval of several months and longer, Rayleigh waves dominate from the coastlines, transitioning to higher mode Lg waves in the higher frequency bands. In contrast, P waves from the coastal and pelagic sources are observed particularly from tropical and equatorial regions. We also identify new patterns of body waves from the Southern Hemisphere perspective, which includes P waves arriving from French Polynesia islands and core phases from North Atlantic Ocean. Our study highlights the importance of utilizing multiple arrays and elucidates the critical roles of the frequency range and bathymetry.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB031032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144300471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lava Rheological Evolution and Flow Emplacement During the Deep Submarine Fani Maoré Eruption (Mayotte)","authors":"Pauline Verdurme,&nbsp;Oryaëlle Chevrel,&nbsp;Etienne Médard,&nbsp;Lucia Gurioli,&nbsp;Carole Berthod,&nbsp;Karoline Brückel,&nbsp;Jean-Christophe Komorowski,&nbsp;Patrick Bachèlery","doi":"10.1029/2024JB030363","DOIUrl":"https://doi.org/10.1029/2024JB030363","url":null,"abstract":"<p>The 2018–2020 lava flow field that built the submarine Fani Maoré volcano (Mayotte, north Mozambique Channel) at a water depth of 3,300 m was extensively sampled. We use the petrological analysis of samples collected at high spatial and temporal resolution to provide information on the textural evolution of the submarine lavas and its impacts on lava rheology, and thus on flow emplacement. Although the crystal content is lower than 10%, we observed two populations of crystals: (a) the micro-phenocrysts which mostly display skeletal shapes suggesting rapid growth upon magma ascent most likely due to decompression-driven crystallization, (b) the microlites resulting from post-emplacement groundmass crystallization. Combining both petrological and geochemical analyses, and applying rheological models, we show that lava viscosity increases from 158 ± 21 to 608 ± 134 Pa·s considering rigid bubbles or from 36 ± 5 to 485 ± 130 Pa·s considering deformable bubbles. Together with the waning ascent velocity and the decreasing effusion rates, this correlates with the evolution of lava flow emplacement dynamics, from long sheet lava flows to shorter flows exhibiting pillow mounts and multiple breakouts.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030363","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144300470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the Performance of GRACE-FO KBR and LRI in Detecting Mass Changes Using Along-Orbit Range-Accelerations","authors":"Zitong Zhu,&nbsp;Changqing Wang,&nbsp;Yihao Yan,&nbsp;Yuhao Xiong,&nbsp;Qinglu Mu,&nbsp;Haoming Yan,&nbsp;Zizhan Zhang","doi":"10.1029/2024JB029428","DOIUrl":"https://doi.org/10.1029/2024JB029428","url":null,"abstract":"<p>Gravity Recovery and Climate Experiment Follow-On is equipped with two inter-satellite ranging systems, notably the K-Band ranging (KBR) and the more precise Laser Ranging Interferometer (LRI), which enable the detection of variations in Earth's gravity. Assessing the differences between KBR and LRI is beneficial for understanding the performance of future LRI-only gravity satellite missions. However, due to limitations imposed by temporal aliasing errors, the advantages of LRI over KBR for monthly gravity field solutions are not clearly discernible. The along-orbit range-accelerations directly reflect the mass variations, providing a new way to evaluate the differences between LRI and KBR. Therefore, we selected different frequency bands and time scales to compare the along-orbit range-accelerations of KBR and LRI from 2019 to 2021. Analyzing the spatiotemporal-averaged along-orbit data, the results indicate a systematic difference between KBR and LRI, with a scale factor of about 0.977 over the selected 92 basins, while the scale factor is lower over oceanic regions. A comparison of the instantaneous along-orbit data for KBR and LRI reveals that the noise level of LRI in the [15.8–21 mHz] band is at least one order of magnitude lower than that of KBR. After simulating instrument noise, model errors, and time-variable signals, it was determined that KBR noise is likely the primary factor contributing to the systematic difference in capturing temporal signals between LRI and KBR. In addition, regions with a low signal-to-noise ratio (SNR) are more susceptible to noise, which diminishes the correlation between KBR and LRI along-orbit data.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144292291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Triggering Intensity Changes Over Time and Space as Measured by Continuous Waveforms in Southern California","authors":"Huiyun Guo,&nbsp;Emily E. Brodsky,&nbsp;Masatoshi Miyazawa","doi":"10.1029/2024JB030004","DOIUrl":"https://doi.org/10.1029/2024JB030004","url":null,"abstract":"<p>Dynamic triggering of earthquakes is when seismic waves from earthquakes induce seismic activity at a distance. The observability of the seismic wave stresses and their results presents a unique opportunity to understand earthquake interactions and associated hazard implications. The extent and timing of dynamic triggering at given specific stress changes still remain inadequately predicted due to limited studies and data sets. In particular, the requirement for complete, well-characterized catalogs to detect triggering systematically seriously limits the types of studies possible. To address this, we utilized 7-year continuous waveform data from 239 stations in southern California and used PhaseNet for phase picking to identify local earthquakes and measure triggering without constructing any earthquake catalog. We map the triggering intensity over the region and find that overall, the Mojave segment of the San Andreas is the most easily triggered region. However, the spatial pattern changes after the Ridgecrest earthquake and the area appears to become much less prone to triggering, likely due to an exhaustion of the faults near failure in the immediate aftermath of the Ridgecrest sequence. We further observe a slow decay rate of dynamic triggering and conclude that low-frequency waves (0.04–0.1 Hz) may be more effective in dynamic triggering than high-frequency waves (1–3 Hz) which is consistent with a rate-state assisted aseismic creep or hydrological triggering mechanism.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144292878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bi-Segment Fault Rupture and Long-Lasting Intraslab Aftershock Activity During the 2017 Mw 8.2 Tehuantepec, Mexico Earthquake","authors":"Fang Chen,&nbsp;Dun Wang,&nbsp;Shenghui Xu,&nbsp;Bing Yan,&nbsp;Junfeng Zhang,&nbsp;Yicun Guo,&nbsp;Dongdong Yao,&nbsp;Jiancang Zhuang,&nbsp;Gerardo Suárez,&nbsp;Peter Shearer","doi":"10.1029/2024JB030699","DOIUrl":"https://doi.org/10.1029/2024JB030699","url":null,"abstract":"<p>The 8 September 2017 Mw 8.2 Tehuantepec, Mexico earthquake was the second largest normal-faulting earthquake to occur in a shallow subduction environment since 1976 (GCMT catalog), and the earthquake sequence featured an extremely long-lasting and productive aftershock activity that deviated from typical intraslab earthquakes. Here we relocated the early aftershocks within 5 days following the mainshock and investigated the source process of the mainshock using back-projection and finite fault inversion methods. Our results showed that the earthquake rupture propagated along a ∼150-km-long, NW-striking normal fault. After rupturing approximately 100 km, it triggered activity on a ∼40-km-long fault located ∼50 km to the northeast. We employed a stochastic branching model to isolate the background seismicity rate, and compared this rate to those of five other earthquakes of similar magnitudes. The results indicated that the background seismicity of the Mexico event occurred at a much higher rate than those of the other five representative earthquakes. Considering that the rupture planes showed similar dip angles and strikes to those of the outer-rise normal faults, we suggest that the ruptures of the Mw 8.2 earthquake are possibly the reactivation of hydrated outer-rise normal faults in the subducting slab.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144292398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}