Abstract

Currently, the Udina volcanoes (Kamchatka, Klyuchevskaya Volcano Group) are considered extinct. However, at the end of 2017, seismic activation was recorded for the first time since instrumental observations beneath them have been carried out at the middle−upper crustal level. To improve the accuracy in determining the coordinates of hypocenters in the vicinity Udina volcanoes, work was carried out to refine the local velocity model for this area. The velocity structure of the setting was refined using proprietary approaches to determining the coordinates of earthquake hypocenters and reversing the travel-time curves from deep sources. Seismic wave propagation velocities were obtained from data on earthquakes of the Udina seismic activation 2017−2019. The results of the Kamchatka regional seismic network and four additional temporary stations installed specifically to study the Udina seismogenic region were used. A one-dimensional velocity model was obtained for depths up to 40 km: the set of layers in which the longitudinal wave velocity varies linearly at a constant ratio V_P/V_S = 1.85. The model differs significantly from the generalized baseline curve obtained for the northern part of the Klyuchevskaya Volcano Group based on DSS data DSS. The largest differences in velocities are observed in the upper crust (at a depth of up to 4 km) and in the region of the Conrad discontinuity at a depth of ∼20 km In the depth range of 20−25 km, a reduced-velocity layer was revealed.

中文翻译：

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通过区域和临时地震台站记录乌迪纳火山（Kamchatka）下的当地地震。通过反转深源的行程时间曲线来完善速度模型

摘要

目前，乌迪纳火山（堪察加火山，Klyuchevskaya火山群）被认为已灭绝。然而，自2017年底以来，在中上地壳水平进行了仪器观测，这是首次记录了地震活动。为了提高确定乌迪纳火山附近震源坐标的准确性，我们进行了工作以完善该地区的局部速度模型。使用专有方法改进了设置的速度结构，以确定地震震源的坐标并反转了深源的传播时间曲线。地震波传播速度是根据2017-2019年乌迪纳地震激活的地震数据获得的。使用了堪察加地区地震网络和另外四个专门用于研究乌迪纳地震发生地区的临时站的结果。对于深度达40 km的情况，获得了一个一维速度模型：纵向波速度以恒定比率线性变化的一组层V _P / V _S  ＝ 1.85。该模型与基于DSS数据DSS为Klyuchevskaya火山群北部获得的广义基线曲线有显着差异。在上地壳（最深达4 km）和康拉德间断面区域中，在〜20 km深度处观察到最大的速度差异。在20-25 km的深度范围内，速度降低了层被揭示。