Volcanoes- Earthquakes
Campi Flegrei, an area north of the city of Naples in Italy made up of 40 ancient volcanoes. A Slew of recent earthquakes in the active volcanic zone at the north of Naples in 2023 has raised the fear of evacuation in Naples. Across the bay of Naples from Campi Flegrei sits the ancient city of Pompeii, a key tourist attraction in southern Italy, preserving the ruins of volcanic calamities. The most recent eruption of Vesuvius was in 1944 marked by voluminous cloud of hot gases, ash and pyroclastic flows, killing an estimated 30000 people.
Europe’s Super Volcano: Is an eruption in Italy imminent? Click here to Read more.Â
March 1944: The Most Recent Eruption of Mount Vesuvius
How geophysical processes give rise to geophysical events of differing type and magnitude
| Events/volcanoes | Plates | Types of plate boundary and causes of the volcano |
|---|---|---|
| 2010 volcanic events of Eyjafjallajökull in Iceland | Eurasian and North American plates | Iceland lies on the Mid Atlantic Ridge, a constructive plate margin separating Eurasian and North American plates. As the plates move apart, fissure is created and magma fills the magma chamber below due to the mantle convection current. |
Mount St. Helens eruption 2008 Mount St. Helens is a stratovolcano in Washington, the Pacific Northwest region of the United States. | Sits on the plate boundary between Juan de Fuca and the North American plates | Part of the 'Ring of Fire' volcano. Ring of fire is a horseshoe-shaped seismically active belt of earthquake epicentres and the volcanic chain surrounding the Pacific Ocean. It is marked by destructive or convergent plate boundaries. |
| Mount Vesuvius | Eurasian and African tectonic plates. | Vesuvius is located on the west coast of Italy near Naples and is the only active volcano on mainland Europe. As part of the Campanian volcanic arc, it formed over the subduction zone created by the collision of the Eurasian and African tectonic plates. African plate is sinking underneath the Eurasian plate creating a convergent/ destructive plate boundary. |
Campi Flegrei, an area north of the city of Naples in Italy made up of 40 ancient volcanoes. A Slew of recent earthquakes in the active volcanic zone at the north of Naples in 2023 has raised the fear of evacuation in Naples. Across the bay of Naples from Campi Flegrei sits the ancient city of Pompeii, a key tourist attraction in southern Italy, preserving the ruins of volcanic calamities. The most recent eruption of Vesuvius was in 1944 marked by voluminous cloud of hot gases, ash and pyroclastic flows, killing an estimated 30000 people.
Europe’s Super Volcano: Is an eruption in Italy imminent? Click here to Read more.Â
Mechanisms of plate movement including internal heating, convection currents, plumes, subduction and rifting at plate margins
Reading: Prof. Stephen A. Nelson’s paper (Tulane University) on Plate tectonics
Characteristics of volcanoes (shield, composite and cinder) formed by varying types of volcanic eruption; and associated secondary hazards (pyroclastic flows, lahars, landslides)
Characteristics of earthquakes (depth of focus, epicentre and wave types) caused by varying types of plate margin movement and human triggers (dam building, resource extraction)
Volcanic eruption and associated hazard
Prev
Next
Prev
Next
Soil Liquefaction, Tsunami; Landslide : Secondary Hazard Related to Earthquake
Happens when solid materials turns into a liquefied state due to an increase in pressure, most likely as a result of ground shaking during an earthquake. Unconsolidated sediments and materials on the surface may get saturated with water and the entire ground may starts moving, damaging building foundations. Soil liquefaction may cause massive collapse of the buildings and other man made structures such as bridges, dam, pipelines etc. Loosely packed, waterlogged sediments at or near the ground surface are ideal for liquefaction. Liquefaction occurring beneath buildings and other structures can cause major damage during earthquakes. For example, during the California earthquake, 1989, liquefaction of the soils and debris caused major subsidence, fracturing, and horizontal sliding of the ground surface in the Marina district in San Francisco.
Prev
Next
Transverse faults
Transverse faults occur when a block of rock fractures, and the two blocks of rock slide past each other in opposite directions. Transverse faults strike obliquely or perpendicular to the general structural trend of the region. Unusual transverse faults along the Cascadia margin have been discovered in 1990s using sonar and seismic reflection.
