1. Volcanic Hazards and Cities
Nearly all growth on our planet is now occurring in the cities. We volcanologists must carefully consider the needs of those cities and towns located near volcanoes. We must also gird ourselves to work with people from other scientific disciplines and policy makers.

2. Global Urban Population at Risk?
In a comparison of volcanoes with historic volcanic activity vs. cities with populations greater than 100,000, we came up with the observation that there are 60 located where they could be directly affected by eruptions or density currents from those volcanoes.
This population estimate is very low, being based on 1990 census estimates plus the fact that these numbers do not include the many suburban communities that ring most cities.
This doesn’t count the effects of volcanic ash plumes indirectly affecting cities via impact on, for example air traffic and transmission systems for electrical utilities

3. Volcanic Eruption Phenomena and Hazards
“Understanding Volcanic Hazards”—Video produced by the International Association of Volcanology and Chemistry of the Earth’s Interior
Ash fall
Pyroclastic (ash) flows
Lava Flows
Lahars (volcanic mudflows)
Earthquakes
Tsunamis
Volcanic Gases
It is better to take 15 minutes to show a video concerning the basic types of volcanic eruption phenomena at this point

4. Manila, Philippines Population, metro area—10 million
Two caldera complexes, many smaller volcanoes
Last large-scale eruption—Taal, 5380 years ago
Last smaller eruption—Taal, 1977 AD
Manila is surrounded by young and active volcanoes, including two large calderas (products of infrequent but large eruptions that involve many cubic kilometers of pumice and ash, followed by crater collapse--examples here are Taal (5380 years ago) and Laguna de Bay (2.3 to 0.9 million years ago). The pyroclastic flow deposits from both extend under Manila.
Intracaldera eruptions at Taal (within the caldera)—33 since 1572, with the latest in 1977.
PhiVolcs

5. Manila, Philippines Potential risks from: Response and Planning
Ash fall
Pyroclastic (ash) flows
Gases
Lava flows (low probability)
Response and Planning
Mapping of deposits from past eruptions
Geophysical monitoring
Emergency response plans (near Taal, but not Manila)
Education (near Taal), including the public and students
Ash falls can come from many possible sources; the latest being from the 1991 eruption of Mount Pinatubo and closing down air traffic.
Pyroclastic flows are infrequent, with the latest about 5400 years ago, but are catastrophic.
Volcanic gases and lava flows are not hazards in Manila
Comprehensive programs by the Phillipine Institute of Volcanology and Seismology cover monitoring, emergency responseand education on or near Taal, but because of the infrequent eruptions that seriously affect Manila, are limited as to what can be done in metro Manila.

6. Auckland, New Zealand Population— ~1 million
Kermode, 1992
Population— ~1 million
Located in a 360 km2 volcanic field; scoria cones and tuff rings
49 volcanoes erupted during the last 140,000 years
Last eruption about 1000 years ago
Largest city and commercial center in New Zealand.
Is built on and between a volcanic field with scoria cones and tuff rings (broad craters constructed during interaction between rising magma and surface water). Some of the flooded craters are now yacht harbors! Trend over the last 140,000 years leads to an interpretation that eruption frequency and size is increasing...
Pyroclastic flows from calderas in the center of North Island, 200 km south, actually reached what is now Auckland (between 136 and 180 AD)

7. Auckland, New Zealand Potential risks from: Response and Planning
Ash fall; ballistic ejecta
Pyroclastic surges
Gases
Lava flows
Potential hazards of pyroclastic flows from distant calderas
Response and Planning
Mapping of deposits from past eruptions
Geophysical monitoring
Emergency response plans; evacuation and infrastructure protection
Education including the public and students
Disaster mitigation in Auckland includes:
Comprehensive education program for the public regarding volcanic eruptions and their frequency. Studies have been made as to the potential effects of an eruption on the infrastructure, including power, communications and water supplies.

8. Quito, Ecuador Population—1.1 million
Located below Guagua Pichincha, a large composite cone (stratovolcano)
12 eruption periods since 1533 AD.
Erupting now (since October, 1999)
Recent activity since October, 1999—explosive eruptions and dome growth within the crater, which is 2 km wide and 600 m deep. Luckily, the crater is open to the west, away from the city and directs the present pyroclastic flows and mudflows.
Eruption in 1660 AD deposited a 40-cm-thick blanket of pumice in Quito. Four days of darkness and pyroclastic flows.
Are potential ash fall hazards from the many volcanoes surrounding Quito, but Guagua Pichincha is the biggest hazard, being literally in the backyard of the city.
M. Hall
El Comercio

9. Quito, Ecuador Response and Planning Potential risks from:
Mapping of deposits from past eruptions
Geophysical monitoring
Emergency response plans; evacuation, cleanup
Education including the public and students
Especially good reporting on eruptions in the newspapers
Potential risks from:
Ash fall; ballistic ejecta
Pyroclastic flows
Mudflows (lahars)
Gases
If the dome fills the crater, then pyroclastic flows could be the hazard
Ash fall is always a hazard or nuisance, along with secondary mudflows that could follow a heavy ashfall with heavy rain.
Always a problem with ash plumes and civil aviation.
Proximity to the volcano presents a possible risk with regard to volcanic gases.
Involvement of the geophysicists at the Escuela Politecnica, civil defense authorities, posters, good newspaper coverage (important)

10. Seattle/Tacoma, Washington, USA
Population, metro Seattle and Tacoma—3.4 million
Mount Rainier, large composite cone (strato-volcano) east of the cities
Over the last several thousand years, lahars (mudflows) have reached the lowlands every years
Minimal risk from Mt. Baker and Glacier Peak volcanoes (northeast of Seattle)
USGS, 1997
4400 m-high Mt. Rainier is east of and between the cities of Seattle and Tacoma, Washington (at sea level)
Capped with snowfields and glaciers, one of the main hazards are volcanic mudflows peeling off of this massive mountain and flowing down valleys toward Puget Sound. Collapse can occur even if there is no eruption. Last significant mudflow was 500 years ago.
Considerable development of industry and housing on valley floors is problamatic; the developments are on the deposits of the last volcanic mudflows.

11. Seattle/Tacoma, Washington, USA
Response and Planning
Mapping and dating of deposits from past eruptions
Geophysical monitoring, especially seismic detection of collapse and flow monitors along valleys
Emergency response plans for communities along valleys; warning systems
Education—students and public
Potential risks from:
Lahars (mudflows) along valleys radiating from Mt. Rainier
Minimal risk from ash fall; fallout usually to the east
See viewgraph

12. Napoli, Italy
US Army, 1944
Orsi et al., 1998

13. Napoli, Italy Population, metro area— ~3 million
Vesuvius; frequent historic eruptions; last eruption 1944 AD
Phlegrean Fields; two calderas (last large eruption 12,000 years ago); multiple smaller scoria cones and tuff rings (last eruption-1538 AD); restless calderas
Il Mattino, 1906
A very young, active volcanic area, with Vesuvius and the Phlegrean fields.
Last activity was 2 m of uplift, centered in the Phlegrean fields, accompanied by frequent earthquakes from Not certain if this activity was related to rising magma, geothermal processes, or tectonic movement.
Over the last 2000 years, the Phlegrean Fields have risen as much as 7 m (associated with the eruption of 1538) and subsided as much as 6 m below sea level.

14. Napoli, Italy Response and Planning Potential risks from:
Mapping and dating of deposits from past eruptions; tectonic framework
Geophysical monitoring— Seismic, GPS, Gases, Tilt, Temperature variation, etc.
Emergency response plans with Civil Defense, City, Province
Education—students and public; museums; publications; public lectures and TV presentations
Potential risks from:
Earthquakes, uplift and subsidence
Ash fall and pumice fall
Pyroclastic surges and flows
Lava Flows
Gases
Panic
Disaster planning and mitigation is not easy in Napoli
Politics and feuding political parties make planning very difficult. However, through development of first class mapping and dating of deposits from previous eruptions, a world-class geophysical network, education programs, and close work with the city, province and national civil defense authorities, there is some optimism with regard to saving lives should there be an eruption.
Considerable work on the effects of volcanic eruptions on buildings and infrastructure lifelines. Experience with evacuation of sections of the Phlegrean Fields during the seismic crisis.

15. Potential Problems Common to All Volcano Cities

16. To protect cities, along with a healthy budget, the ideal volcanologic underpinnings needed to mitigate risk to cities near volcanoes would include the following——
This is not a complete list, but covers more or less the evolution of the knowledge accumulation process for understanding risk from a volcano.
(walk through the “levels of preparation and understanding”)

17. In a very subjective evaluation, based on experience and the published literature, we made an attempt to evaluate the level of understanding of volcanic risk in the “volcano cities” with populations of over 100,000.

18. The Goal for all “Volcano Cities” during the 21st Century
In the cities evaluation, it became evident that there were less than a half dozen that were on the way to level 4. None have yet achieved that goal, which is a good one for the next century.
What have the volcanologists done so far with regard to mitigating dangers of volcanic activity to cities?
The Goal for all “Volcano Cities” during the 21st Century

19. IDNDR—IAVCEI Decade Volcano Projects-"Reducing Volcanic Disasters”
IDNDR—IAVCEI Decade Volcano Projects-"Reducing Volcanic Disasters” Leader—Chris Newhall
Decade Volcanoes Near Cities:
Colima, Mexico (Colima)
Merapi, Indonesia (Yogyakarta)
Mount Rainier, USA (Seattle-Tacoma)
Santa Maria, Guatemala (Quezaltenango)
Taal, Philippines (Manila, Batangas)
Sakurajima, Japan (Kagoshima City)
Vesuvius, Italy (Napoli)
Galeras, Colombia (Pasto)
Teide, Spain (Santa Cruz de Tenerife)
Avachinsky-Koriaksky, Russia (Petropavlovsk-Kamchatsky
An IAVCEI committee, led by Chris Newhall, has, for the last 9 years been organizing interdisciplinary studies of volcanoes for the International Decade of Natural Disaster Reduction. 15 countries each selected a volcano for study and the results have been the subject of workshops held over the last 6 years or so.
Ten of these volcanoes are located near cities and the business of “bringing volcanology into the city” has an excellent start, thanks to Chris and his committee and the national representatives

20. Disciplines Represented at “Cities on Volcanoes” Workshops
Volcanology
Geographic Information Systems
Public Health
Remote Sensing
Risk Analysis
Civil Engineering
Hydrology
Sociology & Psychology
Civil Defense
City Management
City Planning
Education
The Media (Science Reporters)
City Officials
Insurance Industry
Infrastructure management
The Gruppo Nazionale per Vulcanologia of Italy has co-sponsored two meetings on urban volcanology, the first in Roma in 1975 and the second this year in Roma and Napoli.
“Cities on Volcanoes” was truly interdisciplinary and brought together disciplines as disparate as volcanology and psychology. It involved a week’s field trip around Napoli, where there was ample time to look at real problems and for the people from these disciplines to have time to discuss the problems.
What’s next?
“Cities on Volcanoes-Roma/Napoli, Auckland, and Hilo

21. What should be done to reduce urban volcanic risk in the next century?
Follow the examples for integrated programs of observation, planning and education established in several of the world’s “volcano cities.” Use the potential for Geographic-Information System-based integrated analysis, with heavy use of visualization to present results.
Continue to raise the level of awareness of volcanic risk. Use all available modern educational tools, including the internet. Integrate disaster awareness into the culture (e.g., a “national disaster day”). Annual training of civil defense officials with “virtual reality” scenarios that require real-time responses.
There are several city/volcano combinations where they have made great progress and have set examples for the other cities to follow. Little by little, these large, disparate data sets are being integrated into a GIS base. With this approach, the results can be visualized and put into a form understood by everyone, including policy makers.
With volcanoes there is always the problem of awareness. The crises and restoration are soon forgotten and interest and funding soon drops off. We must get out of this crisis response mode of thinking and maintain a level of awareness (which is done in a few countries).

22. What should be done to reduce urban volcanic risk in the next century
What should be done to reduce urban volcanic risk in the next century? (continued)
Earth scientists working for the cities, with integrated teams, which include environmental scientists, engineers, planners, and social scientists to prepare science- and culture-based emergency response plans. Frequent workshops and meetings like “Cities on Volcanoes.”
Provide the scientific basis for cost-benefit analyses of the value of mitigation and disaster education to decision-makers. Get the politicians and business people involved.
The people who run cities must be convinced that they need teams made up of a variety of the geosciences, atmospheric sciences, GIS, engineering, etc. There is value added for any city or town that is willing to make this change in the way of doing business.
For cities at risk, the traditional makeup of their employees, such as a city engineer working alone, won’t work.

23. Who pays for urban disaster mitigation in the “volcano cities?”
Traditional support
The Nation
The State
National and international disaster relief organizations and NGO’s (always comes after an eruption; very little goes toward mitigation)
The insurance industry (again, after the eruption)
Non-traditional support
The insurance industry (great interest in mitigation and threat reduction)
The utilities (infrastructure)—mitigation, hardening facilities
We must also convince the funding sources that mitigation and education is a solid investment, saving lives and property (and money).
Organizations who provide disaster relief are overworked and under-funded. It is difficult to convince them of the value of mitigation and planning vs. housing and feeding people affected by last week’s disaster
There is increasing work on hazard analysis by insurance companies and the utilities. They realize the value of science-based planning and mitigation.

24. Volcanoes, integrated science, and cities in the 21st century—Suggestions for Professional Geoscience Associations
“GeoRisk” program for the International Unions of Geodesy and Geophysics and Geological Sciences
—the proposed “Decade of Geosciences in the Cities” with each nation picking a “decade city” for integrated scientific study
Urban geoscience curricula need to be encouraged at universities
Communicate the importance of geosciences to mayors, city planners and engineers
We (geoscientists) need to “come out of the woods” and into the cities
What are we doing in our profession?
Using the format of the “Decade volcano” IAVCEI has proposed to the IUGG and IUGS that they focus efforts on the geoscience needs of the world’s cities (not just those with volcanoes). We are proposing that during the “Decade of Geosciences in the City” that each nation pick a city for integrated study. At this time, the only city with long experience in this approach is Rome.
We need to make available to students a curriculum in urban geology.
We volcanologists and geoscientists have had a great century of working mostly “in the woods.” It is time that we left the woods and worked in the cities!!!