Vesuvius Observatory

A hazard watched from beside it

Ferdinand II of Bourbon, King of the Two Sicilies, founded the observatory in 1841 on the Colle del Salvatore, on the slope of Vesuvius, close to where the 79 CE eruption buried Pompeii and Herculaneum. Its first director was the physicist Macedonio Melloni, who had worked on radiant heat, but he was removed in 1848 for political reasons. Luigi Palmieri became director in 1855.

Palmieri designed an electromagnetic seismograph in 1856, an early instrument that recorded the ground motion of volcanic tremors, and during the eruption of 1872 he stayed at his post in the observatory while lava flowed around it.

From a building to a monitoring system

The Observatory kept watch on Vesuvius through the eruptions of the nineteenth and twentieth centuries, the last of which was in 1944. In 2001 it became a section of the Istituto Nazionale di Geofisica e Vulcanologia (INGV), and today a monitoring room in Naples runs around the clock.

It now covers Vesuvius, the Campi Flegrei caldera west of Naples and the island of Ischia, with seismic, deformation, gas and temperature networks, and reports to the Italian Civil Protection Department. The Campi Flegrei has shown raised ground uplift and increased earthquake activity in recent years, and is the focus of much of the work.

Heritage and museum

The historic building houses a museum of instruments and records, opened to the public, which INGV describes as the museum of the first volcanological observatory in the world. The building lies in the Vesuvius National Park, which protects the slopes.

Living beside the hazard

Hundreds of thousands of people live in the zone around Vesuvius that civil protection has defined as at highest risk. The observatory's work is therefore partly scientific and partly a public service: to describe the state of the volcano, to say what has changed and to inform the authorities who decide on alerts and evacuation. It cannot predict an eruption date, but it can say when the volcano's behaviour departs from its baseline. The observatory's long record, from the 1840s, is what makes the baseline meaningful. Nineteenth-century notebooks of Palmieri's seismic and magnetic readings remain in the archive, a baseline that no modern network could recreate.

Instruments and technologies

• Palmieri electromagnetic seismograph A mercury-filled tube or a mass on a spring moved a magnet in a coil, producing a current that was recorded, a way to register ground motion before the modern seismometer.
• Seismic and deformation networks Seismometers, tiltmeters and GNSS receivers around the volcano measure shaking and the swelling of the ground.
• Geochemical monitoring Gas sampling and fumarole temperature measurements track changes in the volcanic system.

The people

• Ferdinand II of Bourbon King who founded the observatory.
• Macedonio Melloni First director, a physicist.
• Luigi Palmieri Director from 1855; builder of the electromagnetic seismograph.

Timeline

• 1841 Founded by Ferdinand II of Bourbon, King of the Two Sicilies.
• 1848 First director Macedonio Melloni is removed for political reasons.
• 1855 Luigi Palmieri becomes director.
• 2001 Becomes a section of INGV.

Key lessons for observation today

• Warning needs a continuous record A volcano watched for generations shows what normal looks like. Anomalies are visible only against a long baseline.
• Multiple sensors, one picture Seismic, deformation and gas networks together tell more than any one. Sensor fusion starts with common time and location.
• Hazard monitoring is a service to the public The observatory reports to civil protection. Observing networks become critical infrastructure when their output drives decisions about people.

Sources

• Italian Civil Protection Department, Vesuvius Observatory
• INGV press note, Vesuvian Observatory museum
• Vesuvius National Park, The Vesuvius Observatory
• Wikipedia, Vesuvius Observatory (secondary)