An innovative study on Stromboli lays the groundwork for a promising technique for monitoring eruptions from their sounds
Hidden in the chaos of the first moments of a volcanic eruption is an ephemeral ring of smoke and ash that can provide scientists with important clues about how dangerous an eruption can be. A new study "captures" these toroidal vortices, in English 'vortex rings', of volcanic origin and their sound on high-speed video, suggesting a new way to monitor eruptions using sound alone.
Volcanic vortex rings are ring eddies that form around the top of an eruptive cloud during the first few seconds of the event, like eddies forming behind an oar pushed into the water. The size, speed and characteristics of these vortices reflect factors useful in assessing how dangerous the eruption is, such as its intensity or the depth of the eruptive vent from which it started.
However, the rings are only noticeable for short periods and can be difficult to measure in small flares. Larger eruptions can instead form more visible vortices, but scientists are not always able to get close enough to make the necessary observations. Also, if the eruption takes place at night or with the volcanic edifice shrouded in ash or clouds, the rings may not be visible.
A new study conducted by a team of volcanologists and physicists specialized in fluid dynamics, entitled “Volcanic Vortex Rings: Axial Dynamics, Acoustic Features, and their Link to Vent Diameter and Supersonic Jet Flow”, made it possible to combine high-speed video with audio recordings focused on the first seconds of Stromboli's eruptions to 'listen' to the volcanic vortex rings.
The study, unique in its audiovisual approach and the first to isolate the sound of the rings, was published in the journal 'AGU Geophysical Research Letters', which publishes high-impact, short-form studies with immediate implications spanning all life sciences. Earth and Space.
“There is a distinctive sound made by the volcanic vortex, which is a low, constant sound. The beauty of vortex rings is that they are stable, which means they emit a constant sound that propagates over time”, explains Jacopo Taddeucci, volcanologist at the National Institute of Geophysics and Volcanology (INGV) and first author of the study.
With this new knowledge about how a volcano's "tune" is related to its eruption, volcanologists can expand our understanding of different volcanic processes and sounds to improve monitoring in cases where visual or other techniques are not usable.
“Even if we don't see the eruption because, for example, the sky is cloudy or we don't have a fixed camera on the volcano, with this new technique we are able to know what is happening by analyzing only the sound”, continues Taddeucci. “My hope is that as we learn more about the sound of eruptions, we will soon be able to monitor changes in an ongoing eruption through noise alone. This is one of the future goals of our research”.
Characteristic sounds
To detect the sound of volcanic eddies, Taddeucci and his collaborators installed high-speed cameras and professional microphones several hundred meters from Stromboli's eruptive vents. They also used a drone to film the volcano while eruptive jets were being emitted, i.e. columns of hot gases, ash and smoke, which reach 100-300 meters in height on the Aeolian volcano. This allowed the team of researchers to measure parameters such as the size of the eruptive vent.
Although the scientists couldn't see the rings they were trying to capture with the naked eye, they did appear by analyzing the high-speed video. After measuring the size and speed of the rings and precisely synchronizing the video with audio, the researchers were able to isolate the low, steady rumble coming from the vortices.
Since the sounds of the vortices were distinctive and constant, the team was able to correlate their frequency with other characteristics of the vortices. In particular, a clear link between the movement of the vortex, its sound and the size of the eruptive vent was highlighted. Other changes in a volcano's "tune," including its eruptive jet, may be related to the internal structure of the vent.
“Vortex rings are quite sensitive to the parameters with which they are generated”, explains Juan José Pena Fernández, fluid mechanics researcher and co-author of the study. “If we record the acoustics generated by a vortex ring we can know quite precisely the conditions that created it. So if there is a change in the behavior of the volcano we might be able to detect it.".
The combination of audio with high-speed images “Makes perfect sense”says Amanda Clarke, a volcanologist at the University of Arizona who was not involved in the study. “I thought he was very creative and intelligent. It is not easy to carry out this kind of measurements in the field at the same time”Clark continues. “In the case of explosive eruptions, volcanic eddies can really 'speak' about the conditions of the source, therefore of the volcano itself. However, it is not easy to extrapolate this information from measurements that are not easily observable”.
Link to the article
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Scientists can listen to volcanic smoke rings to monitor eruptions in the dark
New research lays groundwork for promising new technique for audio-only eruption tracking
Hidden in the chaos of the first moments of a volcanic eruption is an ephemeral ring of smoke and ash that can give scientists important clues about how dangerous an eruption might be. A new study captures these volcanic vortex rings and their sound on high-speed video, potentially pointing to a new way to measure a volcano using only sound.
Volcanic vortex rings are curls of an eruption's plume that form during the first seconds of an eruption, like the twisting ripples in water as you pull an oar through it. The size, speed, and composition of those curls reflect useful factors in assessing how hazardous the eruption is, like how intense the eruption is or how deep in the vent the eruption started.
But the rings are short-lived and can be difficult to measure in small eruptions. Larger eruptions can form visible vortices, but scientists cannot always get close enough to make the necessary observations. If it is dark or the mountain is wreathed in smoke, the rings may not be visible.
In the new study, a team of volcanologists and jet-stream physicists paired high-speed video with audio focused on the first seconds of eruptions at Stromboli volcano in Italy to listen to the vortex rings. The study is unique in its audiovisual approach and is the first to isolate the sound of a volcanic vortex ring.
Their work was published in the AGU journal Geophysical Research Letters, which publishes high-impact, short-format reports with immediate implications spanning all Earth and space sciences.
“There is a characteristic sound which is made by the vortex itself, which is a low, constant sound. The beauty of the of the vortex rings is that they are stable, and that means that they make a constant sound that is propagating over time”, said Jacopo Taddeucci, a volcanologist at Italy's National Institute of Geophysics and Volcanology and lead author of the new study.
With new knowledge about how a volcano's tune is linked to its eruption, volcanologists can continue homing in on different volcanic processes and sounds to improve monitoring when visual or other techniques aren't available.
“Even if we don't see the eruption because it is cloudy or we don't have a permanent camera over there, we will be able to know what is going on just by the sound”, Taddeucci said. “My hope is that by studying the sound of the eruption, we will be able to track changes in those parameters just by the noise. This is one of the future promises of this work”.
Distinctive sounds
To pinpoint the sound of those elusive volcanic vortices, Taddeucci and his collaborators set up high-speed cameras and professional microphones several hundred meters from the vents of Stromboli. They also recorded video from a drone flying over the volcano as it let off steady spurts of eruptive jets, allowing the team to measure parameters like vent size. The jets are supersonic columns of hot gases, ash and smoke, reaching 100 to 300 meters (330 to 1000 feet) high at Stromboli.
Although the team could not see the rings they were trying to capture, when they filtered the video, dark smudges - the vortices - appeared. They measured the rings' size and speed, and by precisely lining up the video with the audio, they isolated the low, steady rumble emanating from the vortices from the roar of the eruptive jet.
Because the vortices' sounds were so distinctive and steady, the team was then able to correlate the frequency with other aspects of the rings. They found a clear link between vortex motion, its sound and vent size, the latter of which they measured with the drone. Other changes in a volcano's 'tune,' including its eruptive jet, could be related to the vent's internal structure.
“Vortex rings are quite sensitive to the parameters with which they are generated”, explained Juan José Pena Fernández, a fluid mechanics researcher and co-author of the new study. “If we record the acoustic generated by a vortex ring, we can know quite precisely the conditions that made it. So if there is a change in the volcano's behavior, we could be able to detect it”.
Combining audio with high-speed visuals “makes perfect sense”, said Amanda Clarke, a University of Arizona volcanologist who was not involved in the study.
“I thought it was very creative and clever. It's not easy to make these kinds of measurements in the field simultaneously”Clark said. “For these kinds of [explosive] eruptions, the vortex structures can really tell you about the source conditions. But it's not easy to tease that information out of the measurements that are not easily observable”.
Link to the article
Hidden in the chaos of the first moments of a volcanic eruption is an ephemeral ring of smoke and ash that can provide scientists with important clues about how dangerous an eruption can be. A new study "captures" these toroidal vortices, in English 'vortex rings', of volcanic origin and their sound on high-speed video, suggesting a new way to monitor eruptions using sound alone.
Volcanic vortex rings are ring eddies that form around the top of an eruptive cloud during the first few seconds of the event, like eddies forming behind an oar pushed into the water. The size, speed and characteristics of these vortices reflect factors useful in assessing how dangerous the eruption is, such as its intensity or the depth of the eruptive vent from which it started.
However, the rings are only noticeable for short periods and can be difficult to measure in small flares. Larger eruptions can instead form more visible vortices, but scientists are not always able to get close enough to make the necessary observations. Also, if the eruption takes place at night or with the volcanic edifice shrouded in ash or clouds, the rings may not be visible.
A new study conducted by a team of volcanologists and physicists specialized in fluid dynamics, entitled “Volcanic Vortex Rings: Axial Dynamics, Acoustic Features, and their Link to Vent Diameter and Supersonic Jet Flow”, made it possible to combine high-speed video with audio recordings focused on the first seconds of Stromboli's eruptions to 'listen' to the volcanic vortex rings.
The study, unique in its audiovisual approach and the first to isolate the sound of the rings, was published in the journal 'AGU Geophysical Research Letters', which publishes high-impact, short-form studies with immediate implications spanning all life sciences. Earth and Space.
“There is a distinctive sound made by the volcanic vortex, which is a low, constant sound. The beauty of vortex rings is that they are stable, which means they emit a constant sound that propagates over time”, explains Jacopo Taddeucci, volcanologist at the National Institute of Geophysics and Volcanology (INGV) and first author of the study.
With this new knowledge about how a volcano's "tune" is related to its eruption, volcanologists can expand our understanding of different volcanic processes and sounds to improve monitoring in cases where visual or other techniques are not usable.
“Even if we don't see the eruption because, for example, the sky is cloudy or we don't have a fixed camera on the volcano, with this new technique we are able to know what is happening by analyzing only the sound”, continues Taddeucci. “My hope is that as we learn more about the sound of eruptions, we will soon be able to monitor changes in an ongoing eruption through noise alone. This is one of the future goals of our research”.
Characteristic sounds
To detect the sound of volcanic eddies, Taddeucci and his collaborators installed high-speed cameras and professional microphones several hundred meters from Stromboli's eruptive vents. They also used a drone to film the volcano while eruptive jets were being emitted, i.e. columns of hot gases, ash and smoke, which reach 100-300 meters in height on the Aeolian volcano. This allowed the team of researchers to measure parameters such as the size of the eruptive vent.
Although the scientists couldn't see the rings they were trying to capture with the naked eye, they did appear by analyzing the high-speed video. After measuring the size and speed of the rings and precisely synchronizing the video with audio, the researchers were able to isolate the low, steady rumble coming from the vortices.
Since the sounds of the vortices were distinctive and constant, the team was able to correlate their frequency with other characteristics of the vortices. In particular, a clear link between the movement of the vortex, its sound and the size of the eruptive vent was highlighted. Other changes in a volcano's "tune," including its eruptive jet, may be related to the internal structure of the vent.
“Vortex rings are quite sensitive to the parameters with which they are generated”, explains Juan José Pena Fernández, fluid mechanics researcher and co-author of the study. “If we record the acoustics generated by a vortex ring we can know quite precisely the conditions that created it. So if there is a change in the behavior of the volcano we might be able to detect it.".
The combination of audio with high-speed images “Makes perfect sense”says Amanda Clarke, a volcanologist at the University of Arizona who was not involved in the study. “I thought he was very creative and intelligent. It is not easy to carry out this kind of measurements in the field at the same time”Clark continues. “In the case of explosive eruptions, volcanic eddies can really 'speak' about the conditions of the source, therefore of the volcano itself. However, it is not easy to extrapolate this information from measurements that are not easily observable”.
Link to the article
---
Scientists can listen to volcanic smoke rings to monitor eruptions in the dark
New research lays groundwork for promising new technique for audio-only eruption tracking
Hidden in the chaos of the first moments of a volcanic eruption is an ephemeral ring of smoke and ash that can give scientists important clues about how dangerous an eruption might be. A new study captures these volcanic vortex rings and their sound on high-speed video, potentially pointing to a new way to measure a volcano using only sound.
Volcanic vortex rings are curls of an eruption's plume that form during the first seconds of an eruption, like the twisting ripples in water as you pull an oar through it. The size, speed, and composition of those curls reflect useful factors in assessing how hazardous the eruption is, like how intense the eruption is or how deep in the vent the eruption started.
But the rings are short-lived and can be difficult to measure in small eruptions. Larger eruptions can form visible vortices, but scientists cannot always get close enough to make the necessary observations. If it is dark or the mountain is wreathed in smoke, the rings may not be visible.
In the new study, a team of volcanologists and jet-stream physicists paired high-speed video with audio focused on the first seconds of eruptions at Stromboli volcano in Italy to listen to the vortex rings. The study is unique in its audiovisual approach and is the first to isolate the sound of a volcanic vortex ring.
Their work was published in the AGU journal Geophysical Research Letters, which publishes high-impact, short-format reports with immediate implications spanning all Earth and space sciences.
“There is a characteristic sound which is made by the vortex itself, which is a low, constant sound. The beauty of the of the vortex rings is that they are stable, and that means that they make a constant sound that is propagating over time”, said Jacopo Taddeucci, a volcanologist at Italy's National Institute of Geophysics and Volcanology and lead author of the new study.
With new knowledge about how a volcano's tune is linked to its eruption, volcanologists can continue homing in on different volcanic processes and sounds to improve monitoring when visual or other techniques aren't available.
“Even if we don't see the eruption because it is cloudy or we don't have a permanent camera over there, we will be able to know what is going on just by the sound”, Taddeucci said. “My hope is that by studying the sound of the eruption, we will be able to track changes in those parameters just by the noise. This is one of the future promises of this work”.
Distinctive sounds
To pinpoint the sound of those elusive volcanic vortices, Taddeucci and his collaborators set up high-speed cameras and professional microphones several hundred meters from the vents of Stromboli. They also recorded video from a drone flying over the volcano as it let off steady spurts of eruptive jets, allowing the team to measure parameters like vent size. The jets are supersonic columns of hot gases, ash and smoke, reaching 100 to 300 meters (330 to 1000 feet) high at Stromboli.
Although the team could not see the rings they were trying to capture, when they filtered the video, dark smudges - the vortices - appeared. They measured the rings' size and speed, and by precisely lining up the video with the audio, they isolated the low, steady rumble emanating from the vortices from the roar of the eruptive jet.
Because the vortices' sounds were so distinctive and steady, the team was then able to correlate the frequency with other aspects of the rings. They found a clear link between vortex motion, its sound and vent size, the latter of which they measured with the drone. Other changes in a volcano's 'tune,' including its eruptive jet, could be related to the vent's internal structure.
“Vortex rings are quite sensitive to the parameters with which they are generated”, explained Juan José Pena Fernández, a fluid mechanics researcher and co-author of the new study. “If we record the acoustic generated by a vortex ring, we can know quite precisely the conditions that made it. So if there is a change in the volcano's behavior, we could be able to detect it”.
Combining audio with high-speed visuals “makes perfect sense”, said Amanda Clarke, a University of Arizona volcanologist who was not involved in the study.
“I thought it was very creative and clever. It's not easy to make these kinds of measurements in the field simultaneously”Clark said. “For these kinds of [explosive] eruptions, the vortex structures can really tell you about the source conditions. But it's not easy to tease that information out of the measurements that are not easily observable”.
Link to the article
