Lise Retailleau

Stanford University | SU · Department of Geophysics, School of Earth

In 2019, a new underwater volcano was discovered at 3500 m below sea level (b.s.l.), 50 km east of Mayotte Island in the northern part of the Mozambique Channel. In January 2021, the submarine eruption was still going on and the volcanic activity, along with the intense seismicity that accompanies this crisis, was monitored by the recently created...

The majority of Earth volcanism takes place in the deep ocean. Deep-sea volcanoes are particularly complicated to study due to their remoteness. Very different methods can be used and their combination can lead to crucial information about submarine volcanoes behavior. In Mayotte, Comoros archipelago, efforts have been made to study and monitor the...

Despite significant advancements in understanding crustal melt transport, determining the shallow magmatic architecture at any given volcanic system remains a significant challenge with geophysical methods alone. In this study, we present a new conceptual model combining previously studied models for geomechanical magma reservoirs and dyke-shaped c...

The seismic crisis that began in May, 2018 off the coast of Mayotte announced the onset of a volcanic eruption that started two months later 50 km southeast of the island. This seismicity has since been taken as an indicator of the volcanic and tectonic activity in the area. In response to this activity, a network of stations was deployed on Mayott...

In 2019, a new underwater volcano was discovered at 3500m below sea level (b.s.l.), 50 km east of Mayotte Island in the northern part of the Mozambique Channel. In January 2021, the submarine eruption was still ongoing and the volcanic activity, along with the intense seismicity that accompanies this crisis, is monitored by the recently-created REV...

Seismology is one of the main sciences used to monitor volcanic activity worldwide. Fast, efficient, and accurate seismicity detectors are crucial to assess the activity level of a volcano in near-real time and to issue timely warnings. Traditional real-time seismic processing software uses phase onset pickers followed by a phase association algori...

A new underwater volcano was discovered in 2019 by 3500 meter water depth, 50 km east of Mayotte archipelago in the Mozambique Channel. The eruption is still ongoing and is monitored by the recently created REVOSIMA observatory. The associated seismicity recorded by ocean bottom seismometers forms two deep clusters located 10 km east of Mayotte and...

The brutal onset of seismicity offshore Mayotte island North of the Mozambique Channel, Indian Ocean, that occurred in May 2018 caught the population, authorities, and scientific community off guard. Around 20 potentially felt earthquakes were recorded in the first 5 days, up to magnitude Mw 5.9. The scientific community had little pre-existing kno...

The coupling between the ocean activity driven by winds and the solid Earth generates seismic signals recorded by seismometers worldwide. The 2–10 s period band, known as secondary microseism, represents the largest background seismic wavefield. While moving over the ocean, tropical cyclones generate particularly strong and localized sources of sec...

Correlations of the ambient seismic field recorded by seismic stations carry information about the wave propagation between the stations. They also contain information about the ambient field - both the source of the ambient field, and sources of scattering that contribute to it. The waves that comprise the ambient field are subject to scattering d...

In March 2020, the coronavirus disease 2019 outbreak was declared a pandemic by the World Health Organization and became a global health crisis. Authorities worldwide implemented lockdowns to restrict travel and social exchanges in a global effort to counter the pandemic. In France, and in French overseas departments, the lockdown was effective fro...

Seismic signals can be extracted from ambient noise wavefields by the correlation technique. Recently, a prominent P‐type phase was observed from teleseismic noise correlations in the secondary microseism period band. The phase is named Pdmc in this paper, corresponding to its origin from the interference between the direct P waves transmitting thr...

Body waves can be extracted from correlation functions computed from seismic records even at teleseismic distances. Here we use P and PcP waves from the secondary microseism frequency band that are propagating between Europe and the Eastern United States to image the core–mantle boundary (CMB) and D” structure beneath the North Atlantic. This study...

Human activity causes vibrations that propagate into the ground as high-frequency seismic waves. Measures to mitigate the COVID-19 pandemic caused widespread changes in human activity, leading to a months-long reduction in seismic noise of up to 50%. The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic...

Plain Language Summary Tropical cyclones are most known for their direct impact on the population in terms of destructiveness and economic damage. In addition to satellites, which allow us to monitor these events from the sky, seismic sensors also record the signature of faraway tropical cyclones. Although several studies analyzed these signals, th...

Detections of pP and sP phase arrivals (the so-called depth phases) at teleseismic distance provide one of the best ways to estimate earthquake focal depth, as the P-pP and the P-sP delays are strongly dependent on the depth. Based on a new processing workflow and using a single seismic array at teleseismic distance, we can estimate the depth of cl...

Seismological detection methods are traditionally based on picking techniques. These methods cannot be used to analyze emergent signals where the arrivals cannot be picked. Here, we detect and locate seismic events by applying a beam forming method that combines multiple body-wave phases to USArray data. This method explores the consistency and cha...

The accuracy of Green's function retrieved from noise correlations is mainly limited by the uneven distribution of noise sources at the surface of the Earth. This is particularly true when the scattering is weak, for instance when considering mid-to-long period teleseismic correlations. In this case, noise correlations often exhibit spurious arriva...

The seismic signals continuously recorded by large deployments of sensors at the surface of the Earth leads to an unprecedented amount of data that can be used to get a more detailed image of the Earth structure. It has been shown recently that the correlations of seismic noise converge toward the Green's function even at teleseismic distances. P p...

Detection methods are usually developed to observe earthquakes, and are not relevant to observe long event with emergent signals (e. g. event with sources long in time). We created new method to detect and localize seismic events without prior information about their source. This method explores the consistency and characteristic behavior of telese...

We design an earthquake detection and location algorithm that explores coherence and characteristic behavior of teleseismic waves recorded by a large-scale seismic network. The procedure consists of three steps. First, for every tested source location we construct a time-distance gather by computing great-circle distances to all stations of the net...

We design an earthquake detection and location algorithm that explores coherence and characteristic behavior of teleseismic body waves recorded by a large-scale seismic network. The procedure consists of three steps. First, for every tested source location we construct a time-distance gather by computing great-circle distances to all stations of th...

We report systematic seismic velocity variations in response to tidal deformation. Measurements are made on correlation functions of the ambient seismic wavefield at 2–8 Hz recorded by a dense array at the site of the Piñon Flat Observatory, southern California. The key observation is the dependence of the response on the component of wave motion a...

We present an analysis of the M-w = 5.3 earthquake that occurred in the Southeast Indian Ridge on 2010 February 11 using USArray data. The epicentre of this event is antipodal to the USArray, providing us with an opportunity to observe in details the antipodal focusing of seismic waves in space and time. We compare the observed signals with synthet...

We design an earthquake detection and location algorithm that explores coherence and characteristic behavior of teleseismic waves recorded by a large-scale seismic network. The procedure consists of three steps. First, for every tested source location we construct a time-distance gather by computing great-circle distances to all stations of the net...

We present an analysis of records by the USArray stations of an earthquake that occurred on the Southeast Indian Ridge on February 11, 2010. The epicenter of this event is antipodal to the USArray providing us with an opportunity to observe in details the antipodal focusing of seismic wave in space and time. We compare the observed signals with syn...

We use ambient noise cross correlations to monitor slight changes in seismic velocities. The analysis of the records during a M7.5 slow slip event in the Mexican subduction zone suggests that the observed velocity change could be related with the volumic strain rate (Rivet et al., 2011). This observation is surprising when considering the level of...