Volcanic tremor is a sustained seismic signal associated with volcanic unrest and is often linked to movement of magmatic fluids in the subsurface. However, signals with similar spectral content can be generated by other surface processes. Hence, one of the best ways of distinguishing between different possible mechanisms is by tracking the location of its source, which is also important for mitigating volcanic risk. Due to its emergent nature, tremor cannot be located using travel-time based methods, therefore alternatives such as amplitude-based techniques or array analysis must be used. Dense, small-aperture arrays are particularly suited for analyzing volcanic tremor, yet costs associated with installation and maintenance have meant few long-term or permanent seismic arrays in use for routine monitoring. Given the potential for wider usage of arrays, this work presents a python-based software tool that uses array data and array processing techniques to analyze and locate volcanic tremor signals. RETREAT utilizes existing routines from the open-source ObsPy framework to carry out analysis of seismic array data in real-time and performs f-k (frequency-wavenumber) analysis, or Least-Squares beamforming, to calculate the backazimuth and slowness in overlapping time windows, which can help track the location of volcanic tremor sources. A graphical, or web-based, interface is used to configure a set of input parameters, before fetching chunks of waveform data and performing the array analysis. On each update the tool returns several plots, including timeseries of the backazimuth and slowness, a polar representation of the power and a map of the array with dominant backazimuth overlaid. The tool has been tested using real-time seismic data from the small-aperture SPITS array in Spitsbergen, as well as on data from an array deployed during the 2014 eruption of Bárðarbunga volcano, Iceland. Configuration files and waveform data for these examples are supplied with the distribution. RETREAT can also be used for infrasound and has been tested on infrasonic array data recorded at Mt. Etna, Italy. RETREAT is intended for use in real-time monitoring settings and it is hoped that it will facilitate greater use of arrays in tracking volcanic tremor sources in real-time, thereby enhancing monitoring capabilities.

火山震颤是与火山震荡有关的持续地震信号，通常与地下岩浆流体的运动有关。但是，具有相似光谱含量的信号可以通过其他表面处理生成。因此，区分不同可能机制的最佳方法之一是跟踪其来源，这对于减轻火山风险也很重要。由于其出现的性质，无法使用基于行进时间的方法来定位震颤，因此必须使用基于振幅的技术或阵列分析等替代方法。密集的小孔径阵列特别适合于分析火山震颤，但是与安装和维护相关的成本意味着很少有长期或永久性地震阵列可用于常规监测。鉴于可能广泛使用阵列，这项工作提出了一个基于python的软件工具，该工具使用阵列数据和阵列处理技术来分析和定位火山震颤信号。RETREAT利用开源ObsPy框架中的现有例程对地震阵列数据进行实时分析，并执行fk（频率-波数）分析或最小二乘波束成形，以计算重叠时间窗口中的后方位角和慢度，可以帮助追踪火山震源的位置。在获取波形数据块并执行阵列分析之前，可使用图形或基于Web的界面来配置一组输入参数。每次更新时，该工具都会返回多个图，包括后方位角和慢度的时间序列，功率的极坐标表示，以及覆盖有主要后方位角的阵列图。该工具已使用Spitsbergen的小孔径SPITS阵列的实时地震数据以及2014年冰岛Bárðarbunga火山喷发期间部署的阵列数据进行了测试。这些示例的配置文件和波形数据随发行版一起提供。RETREAT也可以用于次声，并且已经在Mt记录的次声阵列数据上进行了测试。意大利埃特纳火山。RETREAT旨在用于实时监视环境，并希望它将有助于更多地使用阵列来实时跟踪火山震源，从而增强监视能力。该工具已使用Spitsbergen的小孔径SPITS阵列的实时地震数据以及2014年冰岛Bárðarbunga火山喷发期间部署的阵列数据进行了测试。这些示例的配置文件和波形数据随发行版一起提供。RETREAT也可以用于次声，并且已经在Mt记录的次声阵列数据上进行了测试。意大利埃特纳火山。RETREAT旨在用于实时监视环境，并希望它将有助于更多地使用阵列来实时跟踪火山震源，从而增强监视能力。该工具已使用Spitsbergen的小孔径SPITS阵列的实时地震数据以及2014年冰岛Bárðarbunga火山喷发期间部署的阵列数据进行了测试。这些示例的配置文件和波形数据随发行版一起提供。RETREAT也可以用于次声，并且已经在Mt记录的次声阵列数据上进行了测试。意大利埃特纳火山。RETREAT旨在用于实时监视环境，并希望它将有助于更多地使用阵列来实时跟踪火山震源，从而增强监视能力。RETREAT也可以用于次声，并且已经在Mt记录的次声阵列数据上进行了测试。意大利埃特纳火山。RETREAT旨在用于实时监视环境，并希望它将有助于更多地使用阵列来实时跟踪火山震源，从而增强监视能力。RETREAT也可以用于次声，并且已经在Mt记录的次声阵列数据上进行了测试。意大利埃特纳火山。RETREAT旨在用于实时监视环境，并希望它将有助于更多地使用阵列来实时跟踪火山震源，从而增强监视能力。