An analysis of multi‐channel seismic reflection data integrating reflection tomography, pre‐stack depth migration, AVO analysis, seismic modelling and seismic attribute analysis was used to investigate the Miocene – Quaternary stratigraphy of the Gulf of İzmir, western Anatolia. In this area, the east‐west oriented Gediz graben intersects with the NE‐SW oriented Bakırçay Graben. A velocity‐depth model together with pre‐stack depth migration allowed two seismic stratigraphic units (SSU1 and SSU2) to be distinguished. These units can be correlated with the stratigraphic succession at the offshore Foça‐1 well and correspond to the Upper Miocene to Recent Bozköy, Ularca and Bayramiç Formations with a combined thickness of 1.75 km. The units rest on acoustic basement (SSU3) which has a basin‐and‐ridge morphology, and which corresponds to the Lower‐Middle Miocene Yuntdağ Volcanics. A number of lateral velocity variations were identified. In particular, a ~90 m wide and ~500 m long lenticular‐shaped low‐velocity zone with an interval velocity of 1.68 km/s was identified in the Quaternary Bayramiç Formation. The structure is bounded by negative reflections whose amplitude increases with offset at the top and by strong positive reflections whose amplitude increases with offset at the base, interpreted as possible bright and flat spots respectively. These amplitude events point to the presence of gas‐saturated sediments within the study area. The lenticular structure is bounded by strike‐slip faults on either side, and by a Miocene – Pliocene unconformity surface below and by shales of the Bayramiç Formations above. It is therefore interpreted as a possible structural – stratigraphic trap. The strike‐slip faults may allow the migration of hydrocarbons from source rocks located at greater depths. The presence of a low‐velocity zone above the lenticular structure reaching up to seafloor may indicate the upward leakage of hydrocarbons from the trap. These observations will contribute to future hydrocarbon exploration activities in the study area.

中文翻译：

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上中新世的地震事件-伊兹密尔湾（胶州）的上新世沉积演替：对油气勘探的意义

利用反射层析成像，叠前深度偏移，AVO分析，地震建模和地震属性分析对多通道地震反射数据进行了分析，以研究安纳托利亚西部伊兹密尔湾的中新世-第四纪地层。在这个地区，东西向的Gediz en片与NE-SW的BakırçayGraben相交。速度深度模型与叠前深度偏移一起可以区分两个地震地层单元（SSU1和SSU2）。这些单元可以与海上Foça-1井的地层演替相关，并且对应于上中新世至最近的Bozköy，Ularca和Bayramiç组，总厚度为1.75 km。这些单元位于具有盆地和山脊形态的声学地下室（SSU3）上，对应于中新世下云塔达火山。确定了许多横向速度变化。特别是在第四季贝拉米奇组中发现了一个约90 m宽和约500 m长的透镜状低速带，其间隔速度为1.68 km / s。该结构受负反射的限制，负反射的幅度随顶部的偏移而增加，而强烈的正反射的幅度随基础的偏移而增加，分别被解释为可能的亮点和平坦点。这些振幅事件表明研究区域内存在气体饱和沉积物。柱状体结构的两侧是走滑断层，下方是中新世-上新世不整合面，上方是Bayramiç组的页岩。因此，它被解释为可能的构造-地层圈闭。走滑断层可能允许烃从更深层的烃源岩中运移。透镜状结构上方直至海底的低速带的存在可能表明碳氢化合物从捕集阱向上泄漏。这些观察将有助于研究区域未来的油气勘探活动。