This paper presents volcanic and tectonic features of Shirahama Bank, an unexplored shallow submarine edifice in the northern Ryukyu Arc which was previously poorly mapped, and consequently the nature of its volcanism and tectonism have been poorly understood. New high-resolution (5 m) bathymetry revealed that Shirahama Bank has small volcanic edifices and depressions on its flat top with water depths of 60–150 m. The edifices have pointy summits with steep slopes greater than 30°. Within the depressions, a total of 59 acoustic bubble plumes were detected by shipboard multibeam sonar, suggesting that active volcanic degassing occurs in this region. The bank is dissected entirely by NW–SE to WNW–ESE trending lineaments while the volcanic edifices and depressions on the flat top are undissected. Shirahama Bank was formed by multiple-stages of volcanism. The youngest volcanic stage probably occurred after surface erosion by sea-level low-stand during the late Pleistocene and after tectonic deformation, providing a constraint on the timing of Quaternary volcanism in the northern Ryukyu Arc. Structural control of arc volcanism in the area is observed. The NW–SE to WNW–ESE lineaments identified on and around Shirahama Bank are interpreted as normal faults and form cross-arc graben structures. The young volcanic structures and active bubble plumes at Shirahama Bank and surrounding areas are concentrated within these cross-arc grabens, suggesting that the most recent volcanism is controlled by ~NE–SW extension (arc-parallel or along-arc extension) in the northern Ryukyu Arc. Our results, combined with previous studies, suggest that arc-parallel extension, which differs from the previously known back-arc extension in the Okinawa Trough, plays an important role in arc volcanism during its initial stages.

本文介绍了白滨滩的火山和构造特征，白滨滩是琉球弧北部的一座未勘探的浅海海底建筑，以前的地图绘制很差，因此对其火山作用和构造作用的性质知之甚少。新的高分辨率 (5 m) 水深测量显示，白滨银行在其平坦的顶部有小型火山结构和凹陷，水深为 60-150 m。建筑物有尖顶，陡峭的坡度大于 30°。在凹陷内，舰载多波束声纳共探测到 59 个声泡羽流，表明该地区发生了活跃的火山脱气。该河岸完全被 NW-SE 到 WNW-ESE 趋势线切割，而平顶上的火山结构和洼地未切割。白滨银行是由多个阶段的火山作用形成的。最年轻的火山阶段可能发生在更新世晚期海平面低地表层侵蚀和构造变形之后，限制了琉球弧北部第四纪火山活动的时间。观察到该地区弧形火山作用的结构控制。在白滨银行及其周围确定的 NW-SE 至 WNW-ESE 构造被解释为正断层并形成横弧地堑构造。白滨银行及周边地区的年轻火山结构和活动气泡羽流集中在这些跨弧地堑内，表明最近的火山活动受北部~NE-SW 延伸（弧平行或沿弧延伸）控制琉球弧。我们的结果，结合之前的研究，