بررسی ساختمان‌های تخریب شده و آسیب‌دیده زلزله زنده‌جان؛ مطالعه موردی: روستاهای زلزله‌زده ولسوالی زنده‌جان ولایت هرات- پاییز 1402

بروز زلزله‌های اخیر ولسوالی زنده‌جان ولایت هرات در پاییز 1402 باعث تلفات بیش از 2000 نفر انجامید و بیشتر خانه‌ها و ساختمان‌ها در روستاهای فوق تخریب و ویران شدند. آنچه در این فاجعه از دید فنی قابل توجه است ساخت‌وساز به شیوه سنتی و نامناسب، شکل‌گیری ساختمان‌هایی با اسکلت فلزی، بتنی و دیوار باربر بدون طراحی در مقابل نیروی زلزله است. در مناطق فوق، ساختمان‌ها به چهار دسته تقسیم‌بندی می‌شود. خانه‌های با ساخت و سازه سنتی (گلی)، ساختمان‌های بنایی، ساختمان‌های بتنی و سازه‌های فلزی. خانه‌های گلی به خاطر عدم استحکام در مقابل نیروی زلزله بیشتر از 95 درصد تخریب گردیده که بیشترین تلفات را از خود به‌جای گذاشته‌اند. ساختمان‌های بنایی در رده دوم قرار گرفته که بیشترین آسیب را بعد از خانه‌های گلی از خود به‌جا گذاشته‌اند ولی سقف‌های کمتری بر سر ساکنان فرود آمده است. در روستاهای فوق نیز ساختمان‌های بتنی و سازه‌های فلزی به چشم می‌خورد که بعضی از این سازه‌ها آسیب جدی دیده و تعدادی بدون آسیب پایداری‌شان را حفظ نمودند. اینکه در این زلزله کمتر ساختمانی بدون آسیب باقی مانده است، بدون تردید نقص در برنامه‌ریزی، طراحی، محاسبات اجرا و نظارت هر یک به‌نوبه خود می‌توانند در این حادثه بزرگ نقش داشته باشند.

a study on destroyed and damaged buildings in zindajan earthquakes; case study: earthquake affected villages of zindajan district, herat province-fall 1402

the recent earthquakes in herat city in the zindajan district, occurred between october 7 and 15, with a series of tremors reaching a magnitude of 6.3. the hypocenter of these earthquakes was located in the zindajan district of western afghanistan, resulting in widespread destruction. these earthquakes and their aftershocks have left thousands of already-vulnerable populations living in underserved (white areas) in urgent need of humanitarian and health assistance. to date, nearly 43,400 people across this district have been directly affected, with almost 23% being children under the age of five. significant damage has been reported in the area, with casualties including at least 2000 deaths and more than 2,500 injuries. as of october 19, aftershocks continue to occur, leaving communities in a state of fear and unease. furthermore, over 3,330 homes have been completely destroyed, and extensive damage to infrastructure, including the water supply network, has been reported. this has forced many people to live in tents, open areas, and other temporary shelters. according to seismologists, the epicenters of these earthquakes were situated between the siakhubulak fault in the north and the herat fault in the south. according to satellite data from sentinel-1a, an area measuring 30 km by 15 km, extending east to west around the location of these earthquakes, experienced uplift. meanwhile, the satellite detected subsidence in a small area to the east of the uplifted zone. the seismologists added that the ground deformation was diffuse and inferred that the earthquakes were associated with a blind thrust fault. the fault responsible for the disaster is likely a structure located between the herat and siakhubulak faults. from a technical perspective, what is significant in the impacted area is the construction of buildings with steel and concrete structures, as well as houses made of earth and unreinforced materials that lack design considerations to withstand the forces of an earthquake. according to survey data from the affected villages in the zindajan district, the buildings can be categorized into four types: steel structures, concrete structures, unreinforced structures, and houses built of earth. in this research, over 95 percent of houses built of earth were destroyed due to their insufficient strength to withstand seismic loads, resulting in the highest number of casualties. unreinforced structures were identified as the second most vulnerable causing significant damage; however, fortunately, fewer roofs collapsed onto residents, thereby saving lives. the studied areas also included concrete and steel structures, some of which sustained serious damage, while a few managed to maintain their stability. this research examined the pathology of buildings and houses, as well as the causes of the damages. the findings from this study are presented below. the lack of proper monitoring and evaluation of constructed structures and buildings, particularly those lacking design and proper connections, has resulted in significant damage. a major issue in this disaster was not only the construction of earth-based structures but also other buildings that were not designed to withstand lateral and seismic loads. this deficiency led to the destruction and damage of most buildings during the first earthquake. the results show that despite experiencing four powerful earthquakes measuring above 6.2 on the richter scale, steel structures, concrete structures, and even unreinforced structures collapsed far less frequently than earth-built houses. these more resilient structures maintained their stability and helped save human lives, according to the statistics. it has been said that if houses were built from earth instead of other materials, approximately 95 percent of causalities could be reduced.