| Fissures are potential hazards that often cause severe damage and affect infrastructure,environment,and socio-economic development.Owing to the complexity of the causes of ground fissures,the prediction of fissures remains a challenging task.Accordingly,this study proposes an earth fissure hazard model through a comparative analysis of the Relative Frequency Ratio model(RFR)and four advanced machine learning algorithms,namely Random Forest(RF),extreme gradient boosting(XGBoost),Na?ve Bayes(NB),and KNearest Neighbor(KNN).Using the Qa’ Jahran Basin in Yemen as a case study area,152 fissure locations were recorded via a field survey for the development of an earth fissure inventory map.Further,11 earth fissure conditioning factors,including topographical,hydrological,geological,and environmental factors,were obtained from various data sources.The frequency ratios approach was used to investigate the relationship between these factors and the event of earth fissures.Statistical indices,including a confusion matrix and area under the receiver operating characteristics(AUROC)curve,were employed to compare and validate the results of the algorithm.The obtained results revealed that the RF algorithm(AUROC,0.99)displayed an excellent performance for generating hazard maps compared to the XGBoost model(AUROC,0.98),NB model(AUROC,0.96),KNN model(AUROC,0.88),and FR(AUROC,0.74).In this study,approximately 0.13% to 7.74% of the overall area was found to be very highly vulnerable to earth fissure hazards,2.55% to 29.14% to a high hazard level,2.72% to 41.60% to a moderate hazard level,5.35% to 14.89% to a low hazard level,and 6.71% to 81.64% to a very low hazard level.According to the filed study,it is showed that subsidence is predicted to persist if groundwater levels in the Qa’ Jahran Basin continue to decrease at a pace of around 2.5 m per year.Continued subsidence will almost certainly result in the formation of new fissures in the future.The inventory of earth fissures in the Qa’ Jahran Basin is likely incomplete,as fissures that are not widened by erosion often appear as hairline fractures that are seldom apparent on aerial images and hard to detect during field survey.Existing and future construction in the Qa’ Jahran Basin may be harmed by previously unknown or new earth fractures.The continued growth of fissures may eventually impact neighborhoods fully in Ma’ber district and neighboring villages.Earth fissures could allow polluted surface water to flow directly into the Qa’ Jahran Basin aquifer,which is the basin’s primary source of drinkable water.To manage basin groundwater as a renewable resource and to mitigate the hazards posed by earth fissure formation and land subsidence,it is necessary to define subsiding zones s and subsidence rates within those zones(which are likely to be variable)(techniques such as Li DAR,In SAR,and high precision GNSS/GPS surveying are well suited for this task).In locations known or reported to be fissuring,site specific hazard evaluations are compulsory for new development and,in some instances,existing development.The region’s most sensitive to earth fissure danger were found in the northern part of the basin.The most significant applied conditioning factors were well density,Elevation,water level,land subsidence,groundwater drawdown,and distance to the fault.In the Qa’ Jahran Basin,earth fissures and land subsidence are caused by long-term groundwater withdrawal in outpacing recharging(mining of groundwater).The highest levels of land subsidence and earth fissure development in the Qa’ Jahran Basin are associated with considerable groundwater table fall locations and the existence of compressible fine-grained sediments in the subsurface.Such findings can assist land management planners,local authorities,and decision-makers in the management of present and future earth fissures to protect society and the ecosystem and implement suitable protection measures.The following conclusions draw based on the findings of the investigation:... |
PDF Full Text Request