<p>Phreatic eruptions are a potentially lethal type of volcanic activity that is notoriously difficult to forecast. Understanding the complex processes that make eruptions more likely is a key step towards detecting precursory signals. Here, we employ 3-dimensional numerical models of heat and fluid flow based on field and laboratory data from Whakaari/White Island Volcano in New Zealand to explore the thermal, hydraulic, and geologic conditions that promote phreatic eruptions. Our results show that hydrothermally mineralised low-permeability seals can trap rising steam and magmatic gases until the pressure exceeds the tensile strength of the rock within days to months. Changes in persistent degassing through secondary vents can provide valuable insights into when the main sealed conduit is building to eruption. This study provides new insights into the timescales and mechanisms promoting phreatic eruptions, and a starting point to quantitatively interpret volcanic signals in terms of subsurface activity and eruptive potential.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Phreatic eruptions at Whakaari Volcano driven by hydrothermal mineralisation and magmatic gas input

  • Sophie C. Pearson-Grant,
  • Michael J. Heap,
  • Adrian E. Croucher

摘要

Phreatic eruptions are a potentially lethal type of volcanic activity that is notoriously difficult to forecast. Understanding the complex processes that make eruptions more likely is a key step towards detecting precursory signals. Here, we employ 3-dimensional numerical models of heat and fluid flow based on field and laboratory data from Whakaari/White Island Volcano in New Zealand to explore the thermal, hydraulic, and geologic conditions that promote phreatic eruptions. Our results show that hydrothermally mineralised low-permeability seals can trap rising steam and magmatic gases until the pressure exceeds the tensile strength of the rock within days to months. Changes in persistent degassing through secondary vents can provide valuable insights into when the main sealed conduit is building to eruption. This study provides new insights into the timescales and mechanisms promoting phreatic eruptions, and a starting point to quantitatively interpret volcanic signals in terms of subsurface activity and eruptive potential.