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Regarding passenger safety and railway network serviceability, the effects of earthquakes on underground transportation systems situated in seismically active regions yield a great challenge. The difficulties are exacerbated by poor weathering and difficult geological conditions. The 345 km long Udhampur Srinagar Baramulla Rail Link (USBRL) project...
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... However, earthquakes and their effects, such as slope failure and landslides, have devastating consequences for tunnels and bridges as part of any phase of a transportation network. Jammu and Kashmir, located in the northwestern Himalayas, have seen medium-to large-magnitude earthquake events, including the 2005 Kashmir earthquake, the 2019 Mirpur earthquake, and the 2022 Afghanistan earthquake (Kijko et al. 2003;Durrani et al. 2005;Ansari et al. 2022cAnsari et al. , 2023aQi et al. 2023). According to Indian Standard IS-1893 (BIS 2016), the most recent seismic microzonation map of India divides the entire country into Zones II-V based on historical earthquake and fault data. ...
... In the event of a major earthquake, this region will be severely impacted. Failure of the USBRL project would harm local residents by disrupting the transportation system and normal life routines (Ansari et al. 2023a). Failure of other facilities-the Chenab Bridge, the Anji Khad Bridge, the Salal Dam, the Chenani Nashri Tunnel, and the Jawahar Tunnel-would have a significant economic impact and undoubtedly take a long time to recover from. ...
... cameras and other cutting-edge imaging technology. Detailed visual renderings of masonry projects and their spatial layout can achieve this, according to Ansari, Rao, and Jain (2023). According to Jena and Pradhan (2020), more people are Using Unmanned Aerial Vehicles (UAVs) for structural evaluation since they can improve our understanding of rural seismic sensitivity and increase seismic risk. ...
Using a novel methodology that integrates incremental dynamic analysis (IDA) and unmanned aerial vehicle positioning (POS) analysis, this study aims to assess the seismic risk of brick structures in rural China. This method can collect a lot of data and accurately anticipate seismic damage by combining UAV oblique photography with IDA analysis. Because rural China has many masonry structures, the project will design unique seismic risk mitigation strategies. High-resolution cameras on Unmanned Aerial Vehicles capture realistic photographs of rural brick buildings. The collected data is carefully examined to reveal architectural and structural elements. The project uses dynamic post-processing software from the CHC Geomatics Office to improve UAV-reference station position accuracy. This program analyzes UAV POS data disparities. The findings allow rural Chinese brick buildings to be assessed for seismic sensitivity during unexpected ground shaking occurrences. UAV tilt-photography reduces manpower and expenditures, improving inquiry efficiency. This combination improves seismic risk response. The IDA and UAV POS analysis are essential for earthquake preparedness and risk mitigation. This data-driven method informs lawmakers, urban planners, and disaster management authorities worldwide, improving earthquake engineering and catastrophe resilience programs. This work improves seismic threat assessment and masonry structure fortification, making earthquake-prone buildings safer. Thus, rural communities benefit from it.
... In this study, 12 different bedrock motions from the Himalayan region were taken into account, and DEEPSOIL was used to perform comparable linear seismic response analysis (Hashash et al. 2008;Latha and Garaga 2010;Grasso and Sammito 2022;Ansari et al. 2023b). Four regional Himalayan earthquake events, Uttarkashi (1991), Chamba (1995), Chamoli (1999, and Hindukush (2010) had actual ground motions record data that were taken into consideration for study. ...
... In this study, shear modulus reduction curves and damping ratios for clays and sands established by Seed and Sun (1989), Seed and Idriss (1970), and Idriss (1990) were employed. Due to the presence of new sediments and alluvium deposits close to the Tawi and Ravi Rivers, the PGA surface is extremely low at the maximum places in Jammu, Samba, Kathua, and the central region of Udhampur (Ansari et al. 2023b). ...
Due to the potential seismicity of the region, transportation infrastructure projects in Jammu and Kashmir require resilient design. In the present study, structural integrity and possible seismic hazard are taken into account while modelling seismic loss of tunnelling projects in the Himalayas. For the predicted hazard and vulnerability functions, the impact of seismic exposure, tunnel lining aging, and construction quality are evaluated. The Pir Panjal tunnel is also assessed for seismic risk and structural damage in post-seismic situations while taking source-to-distance effects into account. The proposed vulnerability parameters will be helpful for monitoring, logistical operations, and post-disaster route functionality. For disaster prevention cells in any nation, decision-making and risk assessment are the two key activities that can profit from the findings of this study.
In this article, the failure mechanism of the tunnel under geohazard fault movement and non-uniform seismic load was studied. The study area considered was Atal Tunnel in Himachal Pradesh, India, in the North-West of the Himalayas. A normal fault of 10 m width was considered by varying the fault dip angles of 30°, 45°, 60°, 75°, and 90° along with Geological Strength Index (GSI) values of 20, 40, 60, and 80. The finite element models were analysed under fault movement and 4 ground motions. A fault movement of 0.5 m was applied at the bottom of the fault and hanging wall area. The results showed that fault with 60° dip angle produced more structural forces in tunnel lining under fault movement. The fault with 20 GSI rock mass exhibited higher structural forces in the tunnel lining, irrespective of dip angle. In the case of seismic load, a smaller dip angle generates more structural forces. The tunnel lining in the hanging wall experienced more tensile damage, especially in the direction of seismic wave propagation. The left and right sides of the lining in the footwall area underwent tension, whereas the tunnel crown and bottom experience compression under seismic load.
This study revealed that the East Anatolian Fault and all of its fault segments including the Dead Sea transform have emerged as the most vulnerable active faults for a large earthquake. The Anatolian Plate is sandwiched between Afro-Arabian and Eurasian plates characterized by the two major fault systems viz., the North Anatolian Fault system and the East Anatolian Fault system. Historical data revealed that the frequency of occurrence of large earthquakes (magnitude 7–8) in the North Anatolian Fault system is high, while the same in the East Anatolian Fault system is relatively less. However, the earthquake of February 6, 2023 in the East Anatolian Fault system did not occur as surprise rather lack of proper seismic study on the seismogenic character of the East Anatolian Fault system is to be blamed for the devastation caused by the earthquake. The last major earthquake occurred in 1872, not on the main East Anatolian Fault rather on the branch of the East Anatolian Fault system that connects Cyprus trench in the outer non-volcanic arc with the recurrence period of 150 years. It is observed that the fault segment connecting Cyprus trench was the triggering fault while the main East Anatolian Fault was activated through fault reactivations, new rupture and massive ground liquefaction occurred during 1268, 1872, and 2023 earthquakes causing massive devastations around Adana, Kahramanmaras, Gaziantep, and Antakya. Study of the paleo-earthquake records, tectonics, and geodynamics of the East Anatolian Fault revealed that the Dead Sea transform is likely to be the future triggering fault for transmitting seismogenic forces to all the surrounding active faults in the region. The East Anatolian Fault system including the Dead Sea transform has been evaluated as the fault where slow strain build-up for attaining saturation and release is going-on due to the southward propagation of arc-trench system and the subduction roll-back component of the eastern Mediterranean Sea block. Melts of the subduction roll-back slab is the source of the formation of pseudo-mantle plume and triple junction wherein Dead Sea transform is one of the tectonic elements of the triple junction for future seismogenic triggering agent.
Several studies investigated the occurrence of fires in Africa with numerical modeling or applied statistics; however, only a few studies focused on the influence of El Niño on the fire risk using a coupled model. The study aimed to assess the influence of El Niño on wildfire dynamics in Africa using the SPEEDY-HYCOM model. El Niño events in the Eastern Tropical Pacific were classified via sea surface temperature (SST) anomaly based on a predefined climatology between 1961 and 2020 for the entire time series of SST, obtaining linear anomalies. The time series of the SST anomalies was created for the region between 5° N and 5° S and 110° W and 170° W. The events were defined in three consecutive 3-month periods as weak, moderate, and strong El Niño conditions. The Meteorological Fire Danger Index (MFDI) was applied to detect fire hazards. The MFDI simulated by the SPEEDY-HYCOM model for three El Niño categories across different lagged months revealed relevant distinctions among the categories. In the case of 'Weak', the maximum variability of fire risk observed at time lags (0,-3,-6, and-9 months) was primarily in Congo, Gabon, and Madagascar. The 'Moderate' pattern had similar characteristics to 'Weak' except for the lag-6 months and its occurrence in the equatorial zone of Africa. 'Strong' showed a remarkable impact in East Africa, resulting in high fire risk, regardless of time lags. Precipitation and evaporation simulations (SPEEDY HYCOM) indicated that El Niño categories in Africa need particular attention in the central, southern, and southeastern regions emphasizing the significance of lag-0 and lag-6 (evaporation) as well as lag-0, lag-6, and lag-9 (precipitation). The SPEEDY-HYCOM coupled model in conjunction with the MFDI was efficient in assessing climate variabilities in Africa during El Niño events. This model allows the analysis and prediction of wildfire risks based on El Niño events, providing crucial information for wildfire management and prevention. Its simulations uncover significant variations in risks among different El Niño categories and lagged months, contributing to the understanding and mitigation of this environmental challenge.
The Eastern Anatolia Observatory (DAG), to accommodate a 4-m telescope, is under construction in the city of Erzurum at Karakaya Peak of the Palandöken Mountain Range. Owing to the vulnerability of the telescope and its optical components to earthquakes and the high demand for pointing accuracy for quality astronomical observations, the seismic hazard needs to be reliably determined before any design and construction work begins. A relevant rectangular zone, extending 250 km from the observatory in each direction, is selected as the study area. Then, the seismic hazard at the DAG site is estimated by using the probabilistic hazard analysis method. Using different magnitude scales, several earthquake catalogues are recompiled by converting them into a uniform moment magnitude (Mw) scale, and the seismic sources that could affect the study area are determined. The results are aggregated for epistemic uncertainties using the logic-tree method. Finally, peak ground acceleration (PGA) values are obtained for two recurrence periods corresponding to two different design levels (operating basis and design basis earthquakes) using two different ground motion attenuation models. The disaggregation of the seismic hazard permits association of the PGA estimates with various faults. Disaggregation also provides source information for synthetic ground motion generation. Effects of rupture directivity and topographical amplification are discussed.
