30 Years in the Life of an Active Submarine Volcano: A Time-Lapse Bathymetry Study of the Kick-'em-Jenny Volcano, Lesser Antilles
30 Years in the Life of an Active Submarine Volcano: A Time-Lapse Bathymetry Study of the Kick-'em-Jenny Volcano, Lesser Antilles
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DOI：
10.1002/2017gc007270
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发表时间：
2018-03-01
影响因子：
3.5
通讯作者：
Robertson, R. E. A.
中科院分区：
文献类型：
--
作者：
Allen, R. W.;Berry, C.;Robertson, R. E. A.
有效的监测是查明和减轻火山灾害的一个重要部分。在海底环境中，这比陆上更困难，因为观测通常限于陆基地震网络和不经常的船上调查。自1939年第一次有记录的喷发以来，位于格林纳达北方8公里外的Kick-'em-Jenny（KeJ）火山一直是13次T相信号的来源。这些独特的地震信号，往往与提高体波地震活动一致，被解释为喷发。它们以大约十年的重复间隔发生，但火山作用的直接确认很少。通过在2016年和2017年进行新的测深调查并重新处理跨越30年的4个遗留数据集，我们可以更清晰地了解KeJ的发展情况。处理网格的细胞大小为5米，垂直精度为1-4米的顺序，使我们能够在火山的ediscience的形态变化与T相情节。在观测期间，通过建设性火山作用增加了7.09 x 10（6）m（3）的物质，但由于山体滑坡而损失了5倍的物质。有限的最近的岩浆生产表明，KeJ可能容易受到更大的喷发与更长的重复时间比发生在研究期间，行为更类似于在弧亚气火山作用比以前认为的。KeJ的T相信号有不同的起源，不太可能仅仅是喷出式海底喷发的结果。我们的研究结果证实了重复条带测深调查在评估海底火山危险方面的价值。简明语言摘要Kick-'em-Jenny是一座位于小安的列斯群岛格林纳达附近的海底火山。1939年的一次大喷发将火山物质送到300米高的空中，标志着一个新岛屿的潜在增长。地震仪大约每十年记录一次进一步的活动，但这些事件很少被直接观察到。因此，我们对这座类似于海面下190米的火山所发生的事情知之甚少。在我们的研究中，我们在2016年和2017年对火山进行了测深调查。我们将联合收割机与1985年至2014年期间对火山进行的4次调查相结合，涵盖了这些动荡时期的一些。而不是一个不断增长的圆锥体，我们观察到几个小滑坡从侧翼的踢'em珍妮。近几十年来，从火山锥上脱落的物质远远多于火山爆发时添加的物质，火山的某些部分有规律地生长和坍塌。这种类型的行为也出现在世界各地其他少数研究的水下火山中，这表明这是一个常见的过程。在该项目的下一阶段，我们将根据这些火山过程进一步解码地震信号，以帮助未来对火山的监测。
Effective monitoring is an essential part of identifying and mitigating volcanic hazards. In the submarine environment this is more difficult than onshore because observations are typically limited to land-based seismic networks and infrequent shipboard surveys. Since the first recorded eruption in 1939, the Kick-'em-Jenny (KeJ) volcano, located 8 km off northern Grenada, has been the source of 13 episodes of T-phase signals. These distinctive seismic signals, often coincident with heightened body-wave seismicity, are interpreted as extrusive eruptions. They have occurred with a recurrence interval of around a decade, yet direct confirmation of volcanism has been rare. By conducting new bathymetric surveys in 2016 and 2017 and reprocessing 4 legacy data sets spanning 30 years we present a clearer picture of the development of KeJ through time. Processed grids with a cell size of 5 m and vertical precision on the order of 1-4 m allow us to correlate T-phase episodes with morphological changes at the volcano's edifice. In the time-period of observation 7.09 x 10(6) m(3) of material has been added through constructive volcanism - yet 5 times this amount has been lost through landslides. Limited recent magma production suggests that KeJ may be susceptible to larger eruptions with longer repeat times than have occurred during the study interval, behavior more similar to sub-aerial volcanism in the arc than previously thought. T-phase signals at KeJ have a varied origin and are unlikely to be solely the result of extrusive submarine eruptions. Our results confirm the value of repeat swath bathymetry surveys in assessing submarine volcanic hazards.Plain Language Summary Kick-'em-Jenny is a submarine volcano located near Grenada in the Lesser Antilles. In 1939 a major eruption sent volcanic material up to 300 m into the air, signalling the potential growth of a new island. Seismometers have recorded further activity approximately once a decade, but these events are rarely observed directly. We therefore understand little about what is happening at the volcano similar to 190 m below the sea surface. In our study we conducted bathymetric surveys of the volcano in 2016 and 2017. We combine this with 4 previous surveys of the volcano, made between 1985 and 2014, covering a number of these periods of unrest. Rather than a growing cone, we observe several small landslides from the flanks of Kick-'em-Jenny. In recent decades far more material has fallen away from the cone than has been added in eruptions with some parts of the volcano growing and collapsing with regularity. This type of behavior is also seen in the handful of other studied underwater volcanoes worldwide, suggesting it is a common process. In the next stage of the project we will try to further decode the seismic signals in the light of these volcanic processes to aid future monitoring of the volcano.