Brothers volcano is arguably the most well-studied submarine arc volcano on Earth. Between 1996, when massive sulfides were first recovered by dredging, and 2018, when International Ocean Discovery Program (IODP) Expedition 376 recovered cores from as deep as 453 m below the sea floor at two chemically distinct hydrothermal upflow zones, over 60 conductivity-temperature-depth (CTD) vertical casts and tow-yo operations mapped hydrothermal plumes over and around the edifice by employing hydrothermal tracer-specific sensors. These surveys started in 1999 and were completed during nine separate expeditions at one- to three-year intervals, except for a six-year gap between 2011 and 2017. Hydrothermal plume distributions over this two-decade period show variability in the intensity and vertical rise height of plumes from the four main vent fields (Upper Cone, Lower Cone, NW Caldera, and Upper Caldera, with the latter not discovered until 2017). Upper Cone plumes were more intense than all other sites in 1999, 2002, 2007, and 2009, then significantly diminished from 2011 to 2018. The Lower Cone plume was the most intense in 2004, then the NW Caldera site became the dominant source of hydrothermal particles from 2011 to 2018. Despite the gap of six years between 2011 and 2017, hydrothermal output appears to have increased within the caldera sometime after the 2009 survey while simultaneously decreasing in intensity at the cone sites. This supports other evidence of linkages between the cone and caldera sites in the deep hydrothermal circulation system, and may be related to the predicted deepening of hydrothermal circulation, infiltration of seawater to facilitate “mining” of magmatic brines, and modulation of subseafloor mineralization processes associated with a modeled, pulsed injection of magmatic gasses. The surveys also revealed ways in which the highly variable regional hydrographic environment impacts the flux of hydrothermal products to the surrounding ocean. Plumes from sources located above the caldera rim disperse hydrothermal components without hindrance, but particles and heat from sources within the caldera become trapped and are dispersed episodically by caldera-flushing events. While on site for 18 days in 2018, repeat CTD casts into the deepest part of the caldera, which was isolated from the surrounding ocean, showed a progressive increase in temperature, representing a net heat flux of 79 MW from conductive and advective sources deeper than 1,570 m.

中文翻译：

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新西兰克马德克弧兄弟海底火山热液羽流监测的两个十年

兄弟火山可以说是地球上研究最深入的海底弧火山。从 1996 年首次通过疏浚发现大量硫化物到 2018 年，国际海洋发现计划 (IODP) 第 376 次探险队在海底以下 453 m 深处的两个化学性质不同的热液上流区回收了岩心，电导率温度超过 60深度（CTD）垂直铸造和拖曳操作通过使用热液示踪剂专用传感器绘制了建筑物上方和周围的热液羽流。这些调查于 1999 年开始，在九次独立的探险中完成，间隔为一到三年，2011 年和 2017 年之间有六年的差距除外。这两个十年期间的热液羽流分布显示出强度和垂直上升的变化。四个主要喷口区（上锥体、下锥体、西北火山口和上火山口，后者直到 2017 年才被发现）的羽流高度。1999年、2002年、2007年和2009年，上锥体羽流比所有其他地点都更加强烈，然后从2011年到2018年显着减弱。下锥体羽流在2004年最强烈，然后西北火山口地点成为热液的主要来源2011 年至 2018 年的颗粒物。尽管 2011 年和 2017 年之间有六年的差距，但在 2009 年调查后的某个时间，火山口内的热液产出似乎有所增加，同时锥体地点的强度有所下降。这支持了深层热液循环系统中锥体和破火山口地点之间联系的其他证据，并且可能与预测的热液循环加深、海水渗透以促进岩浆卤水的“开采”以及相关海底矿化过程的调节有关。通过模拟岩浆气体的脉冲注入。调查还揭示了高度变化的区域水文环境影响热液产物流向周围海洋的方式。来自火山口边缘上方来源的羽流可以毫无阻碍地分散热液成分，但来自火山口内来源的颗粒和热量会被捕获并通过火山口冲刷事件偶尔分散。2018 年在现场停留 18 天时，重复 CTD 投射到火山口最深处（与周围海洋隔离），显示温度逐渐升高，表明来自比周围海洋更深的传导源和平流源的净热通量为 79 兆瓦。 1,570 米。