Frequency & Regularity of Hazards
- Volcanic eruptions occur with varying frequency and regularity depending on the type of volcano and its location
- Shield volcanoes tend to be found at constructive plate margins and are typified by high frequency, low magnitude eruptions
- Stratovolcanoes tend to be found at destructive plate margins and are typified by low frequency, high magnitude eruptions
Diagram of a shield volcano
Diagram of a stratovolcano
- Some volcanoes erupt more frequently and regularly than others
- Mount Stromboli in Italy usually erupts every 20-40 minutes
- Mount Pinatubo in the Philippines had not erupted for around 500 years before its eruption in 1991
- Scientists study the geological history of volcanoes (e.g. eruptions and gas emissions) to try to predict when the next eruption might occur
- Volcanic eruptions can occur with few warning signs and do not necessarily follow historical patterns