Chapter Machine Learning in Volcanology: A Review

A volcano is a complex system, and the characterization of its state at any given time is not an easy task. Monitoring data can be used to estimate the probability of an unrest and/or an eruption episode. These can include seismic, magnetic, electromagnetic, deformation, infrasonic, thermal, geochemical data or, in an ideal situation, a combination of them. Merging data of different origins is a non-trivial task, and often even extracting few relevant and information-rich parameters from a homogeneous time series is already challenging. The key to the characterization of volcanic regimes is in fact a process of data reduction that should produce a relatively small vector of features. The next step is the interpretation of the resulting features, through the recognition of similar vectors and for example, their association to a given state of the volcano. This can lead in turn to highlight possible precursors of unrests and eruptions. This final step can benefit from the application of machine learning techniques, that are able to process big data in an efficient way. Other applications of machine learning in volcanology include the analysis and classification of geological, geochemical and petrological “static” data to infer for example, the possible source and mechanism of observed deposits, the analysis of satellite imagery to quickly classify vast regions difficult to investigate on the ground or, again, to detect changes that could indicate an unrest. Moreover, the use of machine learning is gaining importance in other areas of volcanology, not only for monitoring purposes but for differentiating particular geochemical patterns, stratigraphic issues, differentiating morphological patterns of volcanic edifices, or to assess spatial distribution of volcanoes. Machine learning is helpful in the discrimination of magmatic complexes, in distinguishing tectonic settings of volcanic rocks, in the evaluation of correlations of volcanic units, being particularly helpful in tephrochronology, etc. In this chapter we will review the relevant methods and results published in the last decades using machine learning in volcanology, both with respect to the choice of the optimal feature vectors and to their subsequent classification, taking into account both the unsupervised and the supervised approaches

Machine Learning in Volcanology: A Review

A volcano is a complex system, and the characterization of its state at any given time is not an easy task. Monitoring data can be used to estimate the probability of an unrest and/or an eruption episode. These can include seismic, magnetic, electromagnetic, deformation, infrasonic, thermal, geochemical data or, in an ideal situation, a combination of them. Merging data of different origins is a non-trivial task, and often even extracting few relevant and information-rich parameters from a homogeneous time series is already challenging. The key to the characterization of volcanic regimes is in fact a process of data reduction that should produce a relatively small vector of features. The next step is the interpretation of the resulting features, through the recognition of similar vectors and for example, their association to a given state of the volcano. This can lead in turn to highlight possible precursors of unrests and eruptions. This final step can benefit from the application of machine learning techniques, that are able to process big data in an efficient way. Other applications of machine learning in volcanology include the analysis and classification of geological, geochemical and petrological “static” data to infer for example, the possible source and mechanism of observed deposits, the analysis of satellite imagery to quickly classify vast regions difficult to investigate on the ground or, again, to detect changes that could indicate an unrest. Moreover, the use of machine learning is gaining importance in other areas of volcanology, not only for monitoring purposes but for differentiating particular geochemical patterns, stratigraphic issues, differentiating morphological patterns of volcanic edifices, or to assess spatial distribution of volcanoes. Machine learning is helpful in the discrimination of magmatic complexes, in distinguishing tectonic settings of volcanic rocks, in the evaluation of correlations of volcanic units, being particularly helpful in tephrochronology, etc. In this chapter we will review the relevant methods and results published in the last decades using machine learning in volcanology, both with respect to the choice of the optimal feature vectors and to their subsequent classification, taking into account both the unsupervised and the supervised approaches

VINEDA—Volcanic INfrasound Explosions Detector Algorithm

Infrasound is an increasingly popular tool for volcano monitoring, providing insights of the unrest by detecting and characterizing acoustic waves produced by volcanic processes, such as explosions, degassing, rockfalls, and lahars. Efficient event detection from large infrasound databases gathered in volcanic settings relies on the availability of robust and automated workflows. While numerous triggering algorithms for event detection have been proposed in the past, they mostly focus on applications to seismological data. Analyses of acoustic infrasound for signal detection is often performed manually or by application of the traditional short-term average/long-term average (STA/LTA) algorithms, which have shown limitations when applied in volcanic environments, or more generally to signals with poor signal-to-noise ratios. Here, we present a new algorithm specifically designed for automated detection of volcanic explosions from acoustic infrasound data streams. The algorithm is based on the characterization of the shape of the explosion signals, their duration, and frequency content. The algorithm combines noise reduction techniques with automatic feature extraction in order to allow confident detection of signals affected by non-stationary noise.We have benchmarked the performances of the new detector by comparison with both the STA/LTA algorithm and human analysts, with encouraging results. In this manuscript, we present our algorithm and make its software implementation available to other potential users. This algorithm has potential to either be implemented in near real-timemonitoring workflows or to catalog pre-existing databases.This research was partially funded by KNOWAVES TEC2015- 68752 (MINECO/FEDER), by NERC Grant NE/P00105X/1, by Spanish research grant MECD Jose Castillejo CAS17/00154 and by VOLCANOWAVES European Union’s Horizon 2020 Research and Innovation Programme Under the Marie Sklodowska-Curie Grant Agreement no 798480

Volcanic Seismic Event Classification basedon CNN Architectures

This paper explores the use of convolutional neural network architectures in the context of volcanic seismic event classification through the use of gray-level spectrogram images of longperiod and volcano-tectonic seismic events. We combined the architectures with a set of hyperparameter configurations that produced 720 classification models, which were able to learn the morphological pattern described by the gray-level spectrogram images of seismic events...Este artículo explora el uso de arquitecturas de redes neuronales convolucionales en el contexto de clasificación de eventos sísmicos volcánicos mediante el uso de imágenes de espectrogramas en escala de grises de eventos sísmicos de período largo y volcano-tectónicos. Combinamos las arquitecturas con un conjunto de configuraciones de hiperparámetros que produjeron 720 modelos de clasificación, los cuales fueron capaces de aprender los patrones morfológicos descritos por las imágenes de espectrogramas en escala de grises..

Deep-learning for volcanic seismic events classification

In this work, we proposed a new method to classify long-period and volcano-tectonic spectrogram images using six different deep learning architectures. The developed method used three deep convolutional neural networks named: DCNN1, DCNN2, and DCNN3. Also, three deep convolutional neural networks combined with deep recurrent neural networks named DCNN-RNN1, DCNN-RNN2, and DCNN-RNN3 to maximize the area under the curve of the receiver operating characteristic scores on a dataset of volcano seismic spectrogram images. The DCNN-RNN1, DCNN-RNN2, and DCNN-RNN3 models reached the worst results due to the overfitting, and this happened due to the small number of samples per class employed to train these complex models...En este trabajo, proponemos un nuevo método para clasificar entre spectrograms Long-Period y Volcano-Tectonic utilizando seis diferentes arquitecturas de conocimiento profundo. El método desarrollado utiliza tres redes neuronales convolucionales llamadas: DCNN1, DCNN2 y DCNN3. De igual manera tres redes neuronales convolucionales son combinadas con redes neuronales recurrentes llamadas: DCNN-RNN1, DCNN-RNN2, y DCNN-RNN3 para maximizar el valor del area bajo la curva (ROCAUC) en un datases de espectrogramas de eventos sísmicos volcánicos. Los modelos DCNN-RNN1, DCNN-RNN2, y DCNN-RNN3 alcanzaron los desempeños más bajos debido a que presentaron overfitting, y esto puede ser a causa de la pequeña cantidad de muestras por clase utilizadas para entrenar estos modelos ta complejos..