Water column geochemistry data from REVOSIMA MAYOBS4 Cruise

the mayotte volcanological and seismological monitoring network (revosima) was created in response to the sub-marine eruption that started in may 2018. composed by ipgp, brgm, ifremer and cnrs, its main missions are: 1) to observe and study volcanic phenomena through real-time volcano monitoring, 2) to conduct research programs, 3) to communicate, disseminate and inform authorities and civil society.these real-time observations and research can contribute to the prevention, and mitigation of seismic and volcanic risks. the main objective is to collect geological, geophysical and geochemical data over long periods of time to improve the understanding and modeling of volcanic processes at active volcanoes, to allow the systematic elaboration of long-term multi-parameters databases available to the scientific community, and to inform the authorities in charge of civil protection of any change in the volcano activity and after periods of local and regionally felt earthquakes.the mayobs campaigns are carried out to monitor the evolution of the seismic and volcanic phenomenon which has affected the island of mayotte since may 2018. they are carried out as part of an action program financed by the ministry of research, the general directorate of prevention and risks of the ministry of ecological and inclusive transition, with the support of the interministerial delegate for major risks overseas and in conjunction with the other ministries and institutes involved (ipgp, ipgs, brgm, ifremer). they focus on the region east of mayotte. the bathymetric surveys carried out by shom in the volcano area also contribute to the mayobs project.ifremer carried out water column geochemistry measurements during md222-mayobs4 cruise. in the present database, 10 stations were investigated between the 20th and 30th july 2019 using in situ measurements embedded in a ctd-rosette. samples (max. 16 bottles per station) were anaylized onboard and onshore depending on the parameters. the quality controlled and process data are: in situ: salinity (conductivity), temperature, depth, dissolved oxygen, turbidity onboard: ph, alkalinity, dissolved inorganic carbon, dissolved co2 h2 onshore: dissolved ch4, silicates, d13c ch4, d13c co2, he, ne, 3he, 4he

马约特火山学与地震学监测网络（Revosima）的设立，是对2018年5月开始的海底火山喷发事件的响应。该网络由法国地球物理研究所（IPGP）、法国地质与矿业研究局（BRGM）、法国海洋研究所（IFREMER）和法国国家科学研究中心（CNRS）共同组成，其主要任务包括：1）通过实时火山监测来观察和研究火山现象；2）实施研究项目；3）向政府和公众传达信息。这些实时观测和研究有助于预防地震和火山风险，并减轻其影响。其主要目标是长期收集地质、地球物理和地球化学数据，以增进对活跃火山过程中火山现象的理解和建模，从而允许科学界系统地编制长期多参数数据库，并向负责民防的当局通报火山活动的任何变化，以及当地和区域范围内感知到的地震周期。马约特观测（Mayobs）活动旨在监测自2018年5月以来影响马约特岛的地震和火山现象。这些活动作为由研究部、生态包容性转型部预防与风险总局资助的行动计划的一部分实施，得到海外重大风险部际代表的支持，并与相关部门（IPGP、IPGS、BRGM、IFREMER）合作。它们主要关注马约特岛东部地区。法国海洋水文局（SHOM）在该火山区域进行的测深调查也为马约特观测项目做出了贡献。在MD222-Mayobs4巡航期间，IFREMER进行了水柱地球化学测量。在当前的数据库中，2019年7月20日至30日间，利用CTD-罗斯托特式装置的现场测量对10个站点进行了调查。每个站点的样品（每个站点最多16瓶）根据参数在船上和岸上进行分析。质量控制和处理数据包括：现场：盐度（电导率）、温度、深度、溶解氧、浊度；船上：pH值、碱度、溶解无机碳、溶解二氧化碳和氢；岸上：溶解甲烷、硅酸盐、甲烷碳同位素d13C、二氧化碳碳同位素d13C、氦、氖、氚、氦-4。