一个新的单基因火山的诞生很难在空间和时间上进行精确预测。然而,地震活动可以提醒这种喷发的迫在眉睫,因为它通常以小震级地震群的形式出现,在喷发前可持续数周至数月。这些群通常与岩浆有关,岩浆在最终喷发到地表之前在地壳中停滞了不同的时间。由于多种原因,在新的单一火山诞生之前,很少用地震仪记录火山地震群。在过去的 25 年里,在墨西哥米却肯-瓜纳华托火山区西南部的坦西塔罗火山和帕里库廷火山之间发现了六个不同的地震群(1997 年、1999 年、2000 年、2006 年、2020 年和 2021 年)。它们被认为代表岩浆反复尝试到达地表,暗示该地区的岩浆可能会停滞一段时间,以免在一次上升事件中从地幔源头到达地表。为了更好地了解岩浆穿过地壳的迁移路径,我们通过对整个数据集使用相同的方法和速度模型,更精确地重新定位了其中一些地震群。我们的研究结果表明,这些蜂群起源于 Tancítaro NE 侧翼下方的一个小区域内,深度低于海平面 (bsl) 15 至 8 公里。显然,岩浆正试图在这些地壳深度的同一管道网络内到达地表,但在达到约 8 公里 bsl 的深度时停滞不前。研究这些群至关重要,因为它们可能是米却肯-瓜纳华托火山区这一部分新喷发的先兆。这个单基因场一直非常活跃,在全新世期间产生了数十次喷发,最后两次是 Jorullo (1759–1774) 和 Paricutin (1943–1952)。此外,Tancítaro 地区显示了整个区域中全新世火山密度最高的地区之一,使其成为未来单基因火山诞生的可能候选地点。由于这些原因,应尽快安装永久性地震台网。Tancítaro 地区显示了整个区域中全新世火山密度最高的地区之一,使其成为未来单基因火山诞生的可能候选地点。由于这些原因,应尽快安装永久性地震台网。Tancítaro 地区显示了整个区域中全新世火山密度最高的地区之一,使其成为未来单基因火山诞生的可能候选地点。由于这些原因,应尽快安装永久性地震台网。
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Repeated seismic swarms near Paricutin volcano: precursors to the birth of a new monogenetic volcano in the Michoacán-Guanajuato volcanic field, México?
The birth of a new monogenetic volcano is difficult to forecast with precision, both in space and time. Nevertheless, seismic activity can alert of the imminence of such an eruption because it usually occurs as small-magnitude earthquake swarms that can last for a few weeks to months prior to an eruption. These swarms are usually related to magma that becomes stalled in the Earth’s crust for variable periods of time before its eventual eruption at the surface. For several reasons, volcanic seismic swarms have rarely been recorded with seismometers before the birth of a new monogenetic volcano. Over the past 25 years, six distinct seismic swarms (in 1997, 1999, 2000, 2006, 2020, and 2021) were detected between Tancítaro and Paricutin volcanoes, in the southwestern part of México’s Michoacán-Guanajuato volcanic field. They are believed to represent repeated attempts of magma to reach the surface hinting that in this region magma might become stalled for some time, so as to not reach the surface in a single ascent event from its source in the mantle. To better understand the magma’s migration path through the crust, we re-located with greater precision some of these seismic swarms by using the same methodology and velocity model to the entire data set. Our results show that these swarms originated within a small area beneath the NE flank of Tancítaro at depths of between 15 and 8 km below sea level (bsl). Apparently, magma is trying to reach the surface within the same conduit network at these crustal depths, but stalls when reaching a depth of ~ 8 km bsl. It is crucial to study these swarms because they might be precursors to a new eruption in this part of the Michoacán-Guanajuato volcanic field. This monogenetic field has been very active, producing several dozen eruptions during the Holocene, the last two Jorullo (1759–1774) and Paricutin (1943–1952). Furthermore, the Tancítaro area displays one of the highest densities of Holocene volcanoes within the entire field, making it a probable candidate location for the birth of a future monogenetic volcano. For these reasons, a permanent seismic network should be installed as soon as possible.