پايش ميزان جابه‌جايي ارتفاعي پادگانه‌هاي دريايي در سواحل مكران (كنارك تا كلات)

Monitoring Marin Terraces Elevation Movement Rate in The Makran Coasts of Iran (Konarak to Kalat)

پادگانه‌هاي دريايي مجموعه‌اي از عوارض تكتونيكي در ايران هستند و در طول سواحل درياي عمان از جاسك تا گواتر امتداد دارند. اين پادگانه‌ها پيوسته در حال بالا آمدن‌اند و اين امر بر مورفولوژي آن‌ها تأثير زيادي گذاشته است و نمود بارز آن را مي‌توان شكل‌گيري پرتگاه‌هاي مارني‌ـ ماسه‌سنگي در اين مناطق دانست. اما يكي از سؤالات مهم در بررسي اين پادگانه‌ها، برآورد ميزان برخاستگي اين پادگانه‌ها در بخش‌هاي مختلف آن است. هدف از اين تحقيق بررسي و برآورد تغييرات ارتفاعي پادگانه‌هاي دريايي منطقه كنارك تا كلات با استفاده از تصاوير ماهواره‌اي، تكنيك تداخل‌سنجي راداري و همچنين بررسي تأثير آن بر مورفولوژي اين پادگانه‌ها بود. در اين تحقيق از تصاوير ماهواره‌اي رادار ENVISAT در بازه زماني 2003 تا 2010 و از آناليز سري زماني SBAS براي تحليل ميزان جابه‌جايي و تغييرات ارتفاع پادگانه‌هاي دريايي كنارك، گورديم، تنگ و كلات استفاده شد. نتايج حاصل از اين تحقيق بيانگر آن است كه ميزان برخاستگي سواحل در پادگانه‌هاي منطقه مورد مطالعه يكسان نيست و ميانگين ميزان برخاستگي از 0/25 ميلي‌متر در سال در پادگانه كنارك در شرق منطقه مورد مطالعه به سمت غرب تا 0/7 ميلي‌متر در سال در پادگانه كلات افزايش مي‌يابد. در بخش‌هايي از پادگانه‌هاي دريايي، هم‌زمان با برخاستگي، فرونشست‌هايي مشاهده مي‌شود كه دليل آن را مي‌توان شكل‌گيري گسلش‌هاي نرمال در اين منطقه و فرونشيني سطح پادگانه‌ها دانست. اين برخاستگي‌ها و فرونشست‌ها بر مورفولوژي پادگانه‌هاي دريايي تأثير گذاشته و اشكال ژئومورفولوژي همانند پرتگاه‌هاي مارني‌ـ ماسه‌سنگي متعدد را در اين منطقه به وجود آورده است. علاوه بر آن بررسي‌ها نشان مي‌دهد بالاترين سطوح ارتفاعي در پادگانه‌هاي دريايي منطبق بر مناطقي است كه ميزان برخاستگي آن‌ها بيشتر از ساير نقاط است.

Introduction The Coastal terrace is a unique tectonic complication in Iran and covers more than half of the Oman Sea coast from Jask to Quatre. These beaches are constantly rising and this has greatly influenced the morphology of the formation and deformation of Makran coasts marine terrace, which can be seen in the formation of coastal cliffs in these areas. But one of the important questions in the study of these terraces is to estimate the rate of rise of these coasts in its different parts and its impact on the formation of coastlines in these areas. The aim of this study is to investigate the altitude changes of marine terraces in the area from Konarak to Kalat using satellite images and Radar interferometry technique and its effect on the morphology of them. Study area the study area is located on the coast of Makran and between Konarak in the east to Kalat in the west. These terraces are separated by the Gulf of Pozm and Gordim. This coastal area is affected by the Makran subduction zone. Lithologically, the bedrock of Makran coast in eastern Iran includes Upper Miocene to Pliocene sandstones. Fluctuations in the water level and tectonic changes and equilibrium movements of faults in this region have made the tectonic history of this region very complex, especially on the shores of the Oman Sea. Which are especially widespread on the beaches of Makran. Material and Methods In this study, with the aim of investigating the deformation rate of Oman marine terraces between Konarak port and Kalat port, ASAR radar sensor satellite data of ENVISAT were used. The time series studied in this study is between 2003 and 2010 and the data analysis was performed in Sarscape software in ENVI 5.3 environment.the short baseline algorithm was used in order to analyze the time series and estimate the deformation rate of marine terraces, lineation of marine terrace is determined using Geomatica and Landsat 8Oli satellite data and direction of this lineation cpmputed using Rockwork software. Result and Discussion The rate of change ranged from -3.4 to 2.2 and the average displacement rate was about 0.25 mm per year in Konarak terrace. The simultaneous presence of subsidence and uplift in this terraces indicates the different performance of tectonic processes in this area. This indicates that the uplift in Konarak terrace is about 1.8 mm during the study period of more than seven years (03/05/2003 to 07/08/2010). This rate is about 2.78mm for Gourdim terrace and 5.7mm in Kalat. In Makran Marine Barracks, several normal faults have led to the movement of sediments and terraces. These normal faults are associated with regional subsidence of the coastal plain, although this may be locally formed as a result of differential uplift.In addition, the extension of the main lines in the terraces of the study area is mostly east-west, and this trend is in line with the east-west extension of the Makran subduction zone, indicating that the impact of the collapse of the Saudi plate under the crust Iran has led to the transformation of the coastal region of the Oman Sea Conclusion In this study that uses satellite data ENVISAT-ASAR and SBAS model were performed. The uplift and subsidence rate of marine terraces in this part of the Iranian coast was investigated and the results show the appropriate accuracy of this data and model in the study of these geomorphological forms of the coastline. Tectonic activities have different functions in different parts of these areas and this has led to the formation of uplift and subsidence in different parts of these terraces. The height of the uplifted coasts is directly related to their uplift rate and this parameter decreases from the west of the study area (Kalat) to the east. This is inconsistent with previous assumptions about the increase in altitude of marine terraces from west (Jask) to east, and the rate of uplift of terraces could be a function of locally different geological features.but the results show that the average rate of rise of these beaches in the study period is only about 0.45 mm.