Collaborative Research: Event response to an eruption at Axial Seamount

2015年4月24日，美国国家科学基金会资助的海洋观测站计划（OOI）的电缆阵列探测到轴海山可能爆发的开始，预示着8000次小地震和海底火山口中心2.4米的快速下沉。证据表明，熔岩在山顶破火山口内或附近喷发，包括OOI电缆阵列上的仪器记录的温度急剧上升-事件发生后数周内持续高于环境温度0.6-0.7°C。这次喷发可能会严重扰乱山顶破火山口及其周围的热液和生物系统，并提供了解决时间紧迫的科学问题的难得机会，这些问题只能通过近期海底调查来研究。目前计划于2015年8月由国家科学基金会和美国海洋和大气管理局资助的汤普森号R/V与杰森号和自主式潜水器哨兵号前往轴海山的巡航为这种应对提供了一个极好的机会。本次研究增加了3天的时间，以促进时间紧迫的事件响应科学。详细的海底测绘与船上多波束声纳和近底哨兵调查将覆盖火山口和邻近的裂谷区，预计喷发现场（S）的地区。新鲜岩石（如有）将采用210 Po-210 Pb技术进行取样和定年。热液羽流将通过CTD铸件和传感器拖曳来识别。系泊将部署微型自主羽记录仪，以测量温度，光衰减和氧化还原电位。海上团队计划向更广泛的科学界提供样本和数据，用于对海底过程进行有针对性的研究。

On 24 April 2015, the NSF-funded Ocean Observatories Initiative's (OOI) Cabled Array detected the onset of a probable eruption at Axial Seamount, heralded by a swarm of 8000 small earthquakes and a rapid subsidence of the seafloor by 2.4 meters at the center of the caldera. Evidence that lava was erupted in or near the summit caldera includes a dramatic temperature rise recorded by instruments on the OOI Cabled Array-- up to 0.6-0.7°C above ambient sustained for weeks after the event. This eruption is likely to have significantly perturbed the hydrothermal and biological systems in and around the summit caldera, and provides the rare opportunity to address time-critical scientific questions that can only be investigated with the near-term seafloor investigations. A currently scheduled NSF and NOAA funded cruise to Axial Seamount on R/V Thompson with ROV Jason and AUV Sentry in August 2015 provides an excellent opportunity for such a response. This study adds 3 days onto this cruise to facilitate time-critical event response science.Detailed seafloor mapping with shipboard multi-beam sonar and near-bottom Sentry surveys will cover areas of the caldera and adjacent rift zones that are expected eruption site(s). Fresh rock, if located, will be sampled and dated using the 210Po-210Pb technique. Hydrothermal plumes will be discerned with CTD casts and sensor tows. A mooring will be deployed with Miniature Autonomous Plume Recorders to measure temperature, light attenuation, and redox potential. The at-sea team plans to make samples and data available to the broader science community for targeted research on seafloor processes.