Analysis of a global database on quaternary explosive volcanism

Abstract

Large volcanic eruptions, despite their low frequency of occurrence, have the potential to cause massive loss of life and affect the health of humans and animals and cause major economic losses. The knowledge of the evolution of past volcanic processes is key to mitigate the effects of future eruptions. Field studies along with application of diverse techniques of analysis generate volcanic data, such as, eruption ages, petrological classification, estimates of ejected volume, intensity and magnitude. The design of databases on volcano data constitutes a tool for experts in charge of identifying places at risk, forecasting volcano activity, and scientists interested in finding the relation between volcanic eruptions and climate change. A global database on Quaternary explosive on explosive volcanism has been developed as part of the VOGRIPA project and implemented which main aim is to facilitate accessing data on volcanic eruptions for the scientific community. An explosive eruption is included in the database if its magnitude is 4 or above and if it has been dated. Also at least one measure of the eruption magnitude, such as erupted mass, erupted volume or Volcano Explosivity Index (VEI) is required. The use of the age data is examined for periods of time according to the nature of the age data and also considering major Earth events such as glaciations and interglacials. As we go back in the time, peaks in volcanic activity most likely reflect biases of data; however is an increase in the number of explosive eruptions in the 7th to 10th century and in the past 650 years in the global database on explosive volcanism as well as ice core records. Statistical analyses are applied to eruption records to test the linked hypothesis that the volcanism has been constant over the time interval chosen and that there is not under-recording. The hypothesis is in agreement for the period between 15,000 and 45,000 years BP, and for the whole period including only eruptions with Magnitude 7. Number of explosive eruptions with M>4 and active volcanoes back to 40,000 years BP in 2,500 year interval