Volcanic Risk Mitigation Plan

Environment Waikato’s Volcano Risk Mitigation Plan sets out efficient and effective volcano risk management for the Waikato region. Volcano risk management aims to lessen the effects of volcanic hazards such as eruptions, lahars (mud flows) and ashfall by planning for evacuation (where necessary), response and recovery. Risk mitigation plans define the roles of Environment Waikato, district councils, and the community in managing the impacts of potential natural hazard events.

The Waikato region has more volcanic hazards than any other region in New Zealand. This is because:

• A large part of the Taupo Volcanic Zone (TVZ) lies within or next to the Waikato region’s boundaries.
  
• Our region contains three presently or potentially active volcanic centres -Tongariro, Taupo and Maroa.
  
• Many urban areas (for example, Turangi, Taupo, and Tokoroa) lie within the Taupo Volcanic Zone.
  
• These are vital lifelines (roading, rail, power supply lines) in the Taupo Volcanic Zone.

Environment Waikato’s Volcano Risk Mitigation Plan aims to achieve efficient and effective volcano risk management through:

• clarifiying the volcano management roles and responsibilities of various agencies
  
• dealing with the adverse effects of volcanic activity and the management options for minimising them
  
• planning for response, recovery, monitoring and review activities.

Find out more about Volcanic Activity.

View or print Environment Waikato’s Volcano Risk Mitigation Plan from the PDF file below, or order a printed copy of the Plan through our Publications pages.

Volcanic Risk Mitigation Plan
(815 kb, 116 seconds to download, 56k modem)  

Table of contents

Table of contents						i
Executive Summary						iii
Background and explanation						v
1	Introduction					1
2	Pre-eruption: mitigation techniques for non-crisis periods					3
	2.1	Geological studies				3
	2.2	Planning				3
	2.3	Scientific alert levels and science alert bulletins				6
	2.4	Monitoring				6
	2.5	Satellite remote sensing				7
3	During an eruption: a description of different volcanic hazards and mitigation measures for those hazards					9
	3.1	Tephra falls
		3.1.1	People			10
		3.1.2	Agriculture and horticulture			10
		3.1.3	Building structures			13
		3.1.4	Electricity			13
		3.1.5	Water supply			14
		3.1.6	Wastewater networks (stormwater drainage and sanitary sewers)			14
		3.1.7	Sewage treatment plants			14
		3.1.8	Gas			14
		3.1.9	Transportation			14
		3.1.10	Communications			15
		3.1.11	Mechanical, electrical and electronic equipment			15
	3.2	Mitigation measures to tephra fallout				15
		3.2.1	People			15
		3.2.2	Agriculture and horticulture			15
		3.2.3	Building structures			16
		3.2.4	Electricity			16
		3.2.5	Water supply			17
		3.2.6	Wastewater networks (stormwater drainage and sanitary sewers)			17
		3.2.7	Sewage treatment plants			18
		3.2.8	Transportation			18
		3.2.9	Mechanical, electrical and electronic equipment			19
		3.2.10	Ash disposal			19
		3.2.11	Detailed mitigation measures			19
	3.3	Ballistic fallout				20
		3.3.1	Mitigation measures for ballistic fallout			20
	3.4	Lahars				20
		3.4.1	Mitigation measures for lahars			20
	3.5	Pyroclastic flows				22
		3.5.1	Mitigation measures for pyroclastic flows			22
	3.6	Pyroclastic surges				22
		3.6.1	Mitigation measures for pyroclastic surges			22
	3.7	Volcanic blasts				23
		3.7.1	Mitigation measures for volcanic blasts			23
	3.8	Lava flows				23
		3.8.1	Mitigation measures for lava flows			23
	3.9	Debris Avalanches				24
		3.9.1	Mitigation measures for debris avalanches			24
	3.10	Volcanic gases				24
		3.10.1	Mitigation measures for volcanic gases			25
	3.11	Tsunamis and seiches				25
		3.11.1	Mitigation measures for tsunamis and seiches			26
	3.12	Flooding				26
	3.13	Hydrothermal eruptions				26
		3.13.1	Mitigation measures for hydrothermal eruptions			26
	3.14	Volcanic earthquakes				27
		3.14.1	Mitigation measures for volcanic earthquakes			27
	3.15	Electrical discharges				27
		3.15.1	Mitigation measures for electrical discharges			27
	3.16	Other hazards				27
References						29
Appendix I:		Scientific Alert Levels (Johnston, 1997a)				37
Appendix II:		Detailed mitigation measures				38
Appendix III:		1995-1996 Ruapehu Eruptions Survey				52
Tables						5
Table 1:		Educating the public about volcanic hazards (after Gregory 1995; Peterson, 1996; Voight, 1996)				5
Table 2:		Impacts on plants and soil from increasing ash thickness (after Folsom, 1986 and Blong, 1984; in Neild et al., in prep)				11
Table 3:		Periods of high crop risk from ash (after MAF, 1995; Neild et al., 1998)				12
Table 4:		Mitigation measures for volcanic ash and the water supply (after Johnston 1997a, 1997b)				17
Table 5:		Number of survey participants involved in each type of business				55
Table 6:		How respondents solved or fixed problems caused by Ruapehu eruptions				66
Table 7:		Common hints suggested by survey respondents				67
Table 8:		Lifestyle adaptations made in response to Ruapehu eruptions				70
Table 9:		Range of benefits from the Mount Ruapehu eruptions				72
Table 10:		Organisations that respondents turned to for advice or general information during the 1995-1996 Ruapehu eruptions				73
Table 11:		Impact of a volcanic eruption from Mount Ruapehu in different seasons				74
Figures						1
Figure 1:		Summary of volcanic hazards from a composite cone volcano (after Myers et al., 1997)				1
Figure 2:		Volcanic hazard management during non-crisis (pre-eruption) periods (after Johnston and Houghton, 1995)				2
Figure 3:		Summary of the applications of remote sensing for volcanology (after Oppenheimer, 1997)				8
Figure 4:		Ash from Mount Ruapehu carried by southeasterly winds over Lake Taupo during the 1995-1996 Ruapehu eruptions				9
Figure 5:		The interaction of volcanic gases during an eruption (after Johnston, 1997a)				25
Figure 6:		An eruption from Mount Ruapehu on 8 July 1996				53
Figure 7:		Question 2 – What category do you class your business in?				54
Figure 8:		Turnover of businesses that answered the Ruapehu survey (logarithmic scale)				56
Figure 9:		The arrangement of zones around Mount Ruapehu				57
Figure 10:		Question 6 – Please indicate where your home or business is located				58
Figure 11:		Series of graphs looking at the relationship between peoples’ location and how likely they think they would be affected by a future eruption				59
Figure 12:		Respondents’ knowledge of what to do during an eruption				61
Figure 13:		How did you first learn that there was an eruption occurring from Mount Ruapehu?				63
Figure 14:		Location of the respondent versus whether they were affected by the 1995-1996 Ruapehu eruptions				64
Figure 15:		Question 19 – Did you suffer any economic loss related to the Ruapehu eruptions?				69
Figure 16:		Losses (NZ$) suffered by different types of business (Logarithmic scale)				69
Figure 17:		Types of stress suffered as a result of the Ruapehu eruptions				71