Volcanic Eruptions in Ecuador
Dr. Pedro Basabe
Ministry of the Environment, Ecuador
mailto:pbasabe@ambiente.gov.ec

Since September 1998, the common nickname for the highlands of Ecuador, “Volcano Avenue”, revealed its appropriateness when two volcanoes became newly active almost simultaneously: the Guagua-Pichincha volcano, 4,784 m above sea level, 12 km west of Quito, a city of 1,500,000 inhabitants; and Tungurahua volcano, 5,023 m above sea level, located in the centre of the country, in an area with 100,000 inhabitants.

Several studies have been carried out, including hazard maps for both volcanoes (Hall, M. et al., 1988). The Geophysical Institute of the National Polytechnic is in charge of volcanic and seismic monitoring throughout the country.

Quito is mainly threatened by ashfall and mudflows caused by excessive accumulation of ash on the volcano’s slopes and nearby hills. An eruption by Tungurahua would affect small towns like Baños, a tourist resort of 20,000 inhabitants on the foot of the volcano.

The emergency led to increased volcanic monitoring and the carrying out of specific studies, such as modeling the secondary mudflows in Quito, where 42 streams have been blocked to divert any mudflows away from the city. In the event of a medium intensity scenario involving debris, mudflows could reach a volume of between 4,000 and 330,000 m3, and speeds of up to 6.7 miles per second (EPN, SDR/CSS, UNDP, 1998).

Volcanic activity, early warning and emergency management

Towards the end of September 1998, over 1,800 microseismic events, deformations and significant phreatic explosions were reported involving Guagua-Pichincha volcano. A warning was issued to the million and a half inhabitants of Quito and a yellow alert went into effect on 1 October 1998 and remains in place. On 5 September 1999, a phreato-volcanic explosion raised columns of smoke over 20,000 m high and deposited several mm of ash as far as 150 km away. Orange alert was declared and remained in force for several days, after which a yellow alert was reinstated. Respiratory complaints have increased among the population and transport has been affected; the Quito airport, for instance, had to be shut down for five days. Agriculture and cattle farming have also been affected by the ashes.

The eruption process of the Guagua-Pichincha, beginning in late 1998, has encouraged improvements in emergency management, although problems persist involving coordination, set channels of communication and information, and awareness of the situation. The Municipality of Quito has handled the emergency based on technical information, developing an extensive programme of dissemination and citizen participation. The first emissions of the volcano have allowed experts to learn more about the phenomenon and its behaviour, mitigating initial fears. Subsequent emissions were better handled by the authorities in their public warnings, and the public is better informed as to its role. Now the slogan is, “We have to learn to live with ash.” However, in the event of greater volcanic activity, the consequences could be serious, and this will require greater coordination between the institutions in charge of technical monitoring and those entrusted with disaster response, not to mention the public. The key issue is for all stakeholders to know what their role is supposed to be.

Tungurahua volcano became active in September 1998. Microseismic events and deformations have increased since August 1999 and eruptions have increased. Since October 1999, strong volcano-phreatic emissions have taken place, an orange alert was issued and 100,000 people were evacuated, of whom some 16,000 remain in shelters (December 1999). Volcanic activity so far has included pyroclastic and lava flows accumulating in the top half of the volcano. Ashfall has left deposits near the volcano up to 10 cm deep, increasing lava and debris flows. The ash has also spread over several hundred km, as far away as Guayaquil.

Damage to the 45 towns close to the volcano is considerable: tourism and productive activities have ground to a halt. The impact on agriculture, cattle farming and the chicken industry, among others, has upset the population, since there is no end in sight to the disruptions caused by the volcanic eruptions.

The emergency, by and large, has been handled adequately. Early warnings were issued in timely fashion, the population was evacuated promptly, and the needs of refugees have been met. After a certain rigidity in the beginning, the controlled inflow of residents has been allowed to let them visit their properties. However, the future remains unclear. Funds are limited, the population is largely unemployed, and many concerns remain regarding the evacuated areas.
Lessons learned

• Once again, the high vulnerability of Ecuador to destructive natural phenomena has been highlighted, in this case to volcanic eruptions, underscoring the need for appropriate monitoring and hazard, vulnerability and risk assessments.
• Our towns, settlements and infrastructure are located frequently in high-risk areas. Their growth increases vulnerability. Better land-use, settlement and economic planning can no longer be postponed.
• In the case of volcanic eruptions, there is generally enough time to achieve a good level of technical coordination among decision-makers, including the development of contingency plans. However, coordination must improve among other relevant institutions. Moreover, the unpredictability of specific events means that the measures adopted, including early warning, should not be rigid but flexible, adapting themselves to the phenomenon as it unfolds.
• Public information is crucial. Although, at first, the public is alarmed and worries, the repetitive nature of volcanic phenomena soon makes people become habituated to these events, allowing them to manage the emergency more effectively. It is essential for the population to be aware of the various existing hazards and how to respond to them.
• In spite of all the efforts made, there is still some doubt as to whether the level of preparedness is adequate in the event of a sudden severe emergency. One key question is how to handle these frequent eruptions so that interest remains high among the population, the media and the authorities.
• It is well known that the best way of providing information about this kind of situation is through a single official channel. However, freedom of the press makes it easy to gather information from unofficial channels and disseminate it quickly, leading to panic and poor coordination. It is essential to take measures to mitigate these effects, by establishing a relationship of trust between the authorities and the mass media.
• It is increasingly difficult to handle the situation of people displaced for long periods and therefore unable to carry out their productive activities. The need to handle the emergency in the safest possible way must somehow be reconciled with the need of residents to go back to their properties, even if only for a few hours each day. Medium-term contingency plans must therefore be developed. If national capacity is overstretched by the crisis, international assistance must be sought.
• Crops, the soil, the flora and fauna and the environment in general are severely affected by ashfall and other volcanic products. Contingency and reconstruction plans must take into account the damage to these sectors, and solutions must be sought.
• Public health must be monitored closely.
• Finally, we must learn to live with risk, particularly by including this variable in all development and planning activities and underscoring prevention and mitigation