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Volcano Profile: Mt. Vesuvius
The third in the Volcano Profile series finds us examining one of the most dangerous and famous volcanoes in the world: Italy's Mt. Vesuvius.
The latest in my Volcano Profiles Series, we turn to Europe and Vesuvius. You could fill many, many volumes with the works produced on Vesuvius since Roman times. This profile will barely scratch the surface when it comes to the vast geologic and human history surrounding the volcano, but it is a start. If you want to learn more about the archaeology surrounding Vesuvius, try visiting Blogging Pompeii.
VOLCANO PROFILE: MT. VESUVIUS
Mt. Vesuvius in Italy. Image courtesy of Dario Leone.
Paintng of Vesuvius (1774) by Joseph Wright of Derby.
Mt. Vesuvius erupting in 1944. It has now been 65 years since the last eruption of the volcano.
Since 1944, there have been a number of seismic events at Vesuvius, suggesting the magma system is still active under the volcano, which is definitely not surprising. The most recent of these was in 1999, when seismicity was the highest it had been in 50 years. These earthquakes were at 6-km depth under the volcano and likely reflect magma moving into the lower reaches of the system. An interesting study in 1998 suggested a connection between large earthquakes in the Appennines, ~55 km to the north of the volcano. They found that earthquakes in these mountains tended to accompany eruptions of Vesuvius, with an eruption occuring within ten years after seismicity. They conclude that there is "two-way coupling zone, within which normal-faulting events promote eruptions and eruptions promote earthquakes", which is a fascinating localized interconnectedness of tectonics and volcanism.
Projected areas effected by ash fall and pyroclastic flows from a future eruption of Vesuvius.
The Italian government plans to evacuate 600,000 people from the area around Vesuvius if the volcano were to show signs of major activity again. An explosive eruption at Vesuvius could claim 16,000-20,000 lives without proper monitoring and mitigation. This, in itself, is an amazing number and shows the real danger posed by the volcano. The volcano was named one of the "Decade Volcanoes" as well. A commission appointed by Ministry of Defense in 1991 defined two hazard zones - a red zone where most everything would be destroyed by pyroclastic flows and a yellow zone that would be dominantly affected by ash fall (see above), lapilli and lahars. Since then, there have been many studies (pdf link) that have examined the challenge of volcanic hazard mitigation in such a densely populated area. The mitigation plan includes banning new construction in hazards, monetary bonuses for people to live outside the hazard zone, moving public offices outside the hazard zone, changes to the the transportation system to improve evacuation and an information campaign.
Selected resources of Vesuvius:
Vesuvius as the sun rises. Image courtesy of Dario Leone, taken by Dionigi Caputo.
A Mercury-bound spacecraft's noisy flyby of our home planet.
- There is no sound in space, but if there was, this is what it might sound like passing by Earth.
- A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
- Yes, in space no one can hear you scream, but this is still some chill stuff.
First off, let's be clear what we mean by "hear" here. (Here, here!)
Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.
All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.
Image source: European Space Agency
The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.
Into and out of Earth's shadow
In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.
The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."
In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."
When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.
The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.
BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.
MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.
Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.
Erin Meyer explains the keeper test and how it can make or break a team.
- There are numerous strategies for building and maintaining a high-performing team, but unfortunately they are not plug-and-play. What works for some companies will not necessarily work for others. Erin Meyer, co-author of No Rules Rules: Netflix and the Culture of Reinvention, shares one alternative employed by one of the largest tech and media services companies in the world.
- Instead of the 'Rank and Yank' method once used by GE, Meyer explains how Netflix managers use the 'keeper test' to determine if employees are crucial pieces of the larger team and are worth fighting to keep.
- "An individual performance problem is a systemic problem that impacts the entire team," she says. This is a valuable lesson that could determine whether the team fails or whether an organization advances to the next level.