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Last updated on April 24, 2014 at 0:05 EDT

Volcanology

Volcanology is the study of volcanoes, magma, lava, and related geological, geochemical, and geophysical phenomena. The term volcanology comes from the Latin word Vulcan. Vulcan is the ancient Roman god of fire.

A volcanologist is a person who studies the creation of volcanoes, and their current and historic eruptions. Volcanologists frequently visit volcanoes, particularly active ones, to observe volcanic eruptions, collect eruptive products including samples of tephra, lava, and rock. One major focus of enquiry is the prediction of eruptions; currently there is no accurate way to do this, but predicting eruptions, like predicting earthquakes, could save numerous lives.

In 1841, the first volcanological observatory, the Vesuvius Observatory, was founded in the Kingdom of the Two Sicilies. Seismic observations are made utilizing seismographs that are deployed near volcanic areas, watching out for increased seismicity during volcanic events, particularly looking for long period harmonic tremors, which signal magma movement through volcanic conduits.

Surface deformation monitoring includes the use of geodetic methods such as leveling, strain, tilt, angle, and distance measurements through tiltmeters, total stations, and EDMs. This also includes GNSS observations and InSAR. Surface deformation signifies magma upwelling: increased magma supply produces bulges in the volcanic center’s surface.

Gas emissions may be monitored with equipment including portable ultra-violet spectrometers, which analyzes the presence of volcanic gases such as sulfur dioxide; or by infra-red spectroscopy. Increased gas emissions, and especially changes in gas compositions, may signal an impending volcanic eruption.

Changes in temperature are monitored utilizing thermometers and observing changes in thermal properties of volcanic lakes and vents, which might signify upcoming activity.

Satellites are widely utilized to monitor volcanoes, as they allow a large area to be monitored with ease. They can measure the spread of an ash plume. InSAR and thermal imaging can monitor large, scarcely populated areas where it would be too expensive to maintain instruments on the ground.

Other geophysical techniques include monitoring fluctuations and sudden change in resistivity, gravity anomalies or magnetic anomaly patterns that might indicate volcano-induced faulting and magma upwelling.

Stratigraphic analyses includes analyzing tephra deposits and lava deposits and dating these to give volcano eruption patterns, with estimated cycles of intense activity and size of eruptions.

Volcanology has a wide history. The earliest known recording of a volcanic eruption may be on a wall painting dated to about 7,000 BCE found at the Neolithic site in Anatolia, Turkey. This painting has been interpreted as a depiction of a volcano erupting, with a cluster of houses below showing a twin peaked volcano in eruption, with a town at its base. The volcano in the painting may be either Hasan Dag, or its smaller neighbor Melendiz Dag.

The classical world of Greece and the early Roman Empire described volcanoes as the work of gods as science and alchemy had no explanations for their existence. The first attempt at a scientific explanation was undertaken by the Greek philosopher Empedocles, who saw the world divided into four elemental forces, of Earth, Air, Water, and Fire. Volcanoes, Empedocles maintained, were the manifestation of Elemental Fire. Plato contended that channels of hot and cold waters flow in inexhaustible quantities through subterranean rivers. The Christian world explained volcanoes as the work of Satan or the wrath of God, and only miracles could prevent their wrath.

Image Caption: A geologist collecting a lava sample for chemical analyses from an active lava flow on Kilauea, using a rock hammer and a bucket of water. Credit: Hawaii Volcano Observatory, USGS/Wikipedia

Volcanology