Books by "R. Wally Johnson"
3 books found
This study of the young volcanoes of eastern Australia and parts of New Zealand looks at rock types and formation and inclusions of the upper mantle and lower-crustal rocks found in volcanic deposits. It discusses the Earth's crust and the mantle beneath, and the geological evolution in the area over the last 70-80 million years.
Volcanic eruptions have killed thousands of people and damaged homes, villages, infrastructure, subsistence gardens, and hunting and fishing grounds in Papua New Guinea and the Solomon Islands. The central business district of a town was destroyed by a volcanic eruption in the case of Rabaul in 1994. Volcanic disasters litter not only the recent written history of both countries—particularly Papua New Guinea—but are recorded in traditional stories as well. Furthermore, evidence for disastrous volcanic eruptions many times greater than any witnessed in historical times is to be found in the geological record. Volcanic risk is greater today than at any time previously because of larger, mainly sedentary populations on or near volcanoes in both countries. An attempt is made in this book to review what is known about past volcanic eruptions and disasters with a view to determining how best volcanic risk can be reduced today in this tectonically complex and volcanically threatening region.
Wally Johnson and Neville Threlfall re-examine the explosive volcanic eruptions that in 1937–43 killed more than 500 people in the Rabaul area of East New Britain, Papua New Guinea. They reassess this disaster in light of the prodigious amount of new scientific and disaster-management work that has been undertaken there since about 1971, when strong tectonic earthquakes shook the area. Comparisons are made in particular with volcanic eruptions in 1994–2014, when half of Rabaul town was destroyed and then abandoned. A striking feature of historical eruptive periods at Rabaul is the near‑simultaneous activity at Vulcan and Tavurvur volcanoes, on either side of Rabaul Harbour. Such rare ‘twin’ eruptions are interpreted to be the result of a common magma reservoir beneath the harbour. This interpretation has implications for ongoing hazard and risk assessments and for volcano monitoring in the area.