« PreviousContinue »
other earthquakes have taught us many important lessons. Several of these lessons, which have direct bearing on the disaster in Armenia, are as follows:
• The parameters of the fault located near Spitak shaped the nature of the disaster. The Spitak fault, which released the December 7, 1988, earthquake, is a reverse fault that is tectonically related to the much more prominent North Savan fault. Both faults were mapped prior to the earthquake, and these maps showed that the faults had moved in the last 10,000 to 2 million years. The Spitak fault broke the surface on December 7th over a distance of 9 miles, which resulted in nearly 6.6 feet of vertical movement or displacement.
• Unfortunately, as such disasters prove, a community that has not prepared for a damaging earthquake is particularly vulnerable to disaster, especially if damaging earthquakes have occurred in the past. Despite past damaging earthquakes, Armenia was unprepared for the December 7th earthquake. In 1967, a magnitude 5.1 earthquake centered near Spitak caused minor damage. The most significant recent event in the area, a magnitude 6.5 earthquake that occurred on May 28, 1926, caused severe damage in Leninakan (formerly known as Alexanderkan).
• The destructiveness of an earthquake depends on its size, proximity to an urban center, the soil underlying the buildings, facilities, and lifelines in the center, and the state-of-preparedness in the centers.
Villages like Spitak and Stephankan took a "direct hit" in the epicentral region. Leninakan, although 25 miles from the epicenter, sustained heavy damage because the soil underlying the city amplified the ground motion. This phenomenon was similar to that experienced in Mexico City in the September 19, 1985, Mexico earthquake.
• In such a disaster, a community is always working against time. Critical time frames for responses by a community range from a few seconds to centuries, which compounds the difficulties in providing adequate preparation and hazard response. By being better aware of what the timing is of various earthquake hazards and necessary responses, communities can be better prepared.
response and search and rescue activities (90 percent of the people rescued from the collapsed buildings were saved in the first 24 hours).
Years to decades—For community preparedness and recovery programs (a warning of the increased probability for a damaging earthquake in the region was issued prior to the earthquake by Soviet scientists, but the warning had not been acted upon).
Decades to centuries— For the seismic cycles of active faults to come full circle with the consequent fault rupture; that is, another earthquake which begins the cycle again (Armenia has many active faults that have been mapped; determination of their seismic cycle is in progress).
The disaster in Armenia would have been lessened if the earthquake had occurred 5 minutes later when the school children were outside the schools that were destroyed and on their way home for lunch. Although communities have no control over the exact times of earthquakes, there are effective steps that can be taken to lessen effects. In Armenia, greater efforts need to be made to increase the level of personal prepared
ness and increase communitywide preparedness.
• Earthquake predictions and hazards warnings are only of limited value when the responsible society is not able to properly address and implement the scientific knowledge available. Although Soviet authorities had been advised 3 years ago by their scientists of the increased probability of a damaging earthquake in Armenia, the capability to respond at the community level was not yet in place. It is unfortunate that it sometimes takes a disaster of such large proportion to ensure that available scientific expertise and knowledge is used to properly plan for disasters. We in the United States are not as prepared as we should be for similar disasters in many earthquake-prone areas of the country. Only in California, where more than 50 years of earthquake preparedness and mitigation strategies have been studied and implemented, are we able to survive a 7.1 magnitude earthquake like the one that occurred in Santa Cruz, Calif., on October 17, 1989, with only 62 deaths.
• Extensive building damage occurs in earthquakes because we often underestimate the amplitude, frequency composition, and duration of the ground shaking. The Armenian earthquake had a local epicentral intensity of IX-X, whereas the buildings were designed to only withstand an intensity VII, which was only about one-eighth the actual force level of the earthquake. One reason why the building design was not adequate to withstand the ground shaking was that the ground motion amplification properties of the soil had not been taken into account in the zoning and building codes.
We in the United States
are not as prepared as we
should be for similar
disasters in many
of the country.
• Good, quality construction can provide a margin of safety that can help compensate for the uncertainties that scientists and engineers still face in siting and design. The quality of construction and detailing were inadequate in Armenia to meet the force of the earthquake. Modern buildings designed and constructed in the 1970's failed and caused numerous deaths primarily because the floor systems were not constructed and anchored in a way that allowed them to absorb the energy along with the structure.
• Despite whatever preparations are made and however carefully buildings are constructed, almost all earthquakes produce "surprises" because knowledge about the nature and effects of earthquakes is often lacking or what is known has not been properly applied. A damaging earthquake exposes the flaws in siting and design of structures and lifeline systems, construction practices, emergency response, and personal and community preparedness. In each of these areas, through the proper use of scientific information, much can be done to correct these critical flaws and to develop effective response plans to mitigate the effects of natural hazards.
Although the Spitak earthquake was not a surprise in terms of the seismotectonic framework of the region, the disaster brought some harsh realities to light. The first 24 hours of search and rescue efforts were hampered by the winter environment. The disaster also paid grim testimony to the vulnerability of precast reinforced concrete frame buildings, many of which still exist in the Armenian capitol of Yerevan and in other parts of the Soviet Union. Perhaps most emotionally devastating was the extremely high death toll, which, combined with the harsh winter conditions, made burial of the dead difficult and created public health concerns.
Using the Lessons Learned
On May 23-27, 1989, representatives of the United States team that went to Armenia after the December 7th earthquake and other specialists met with their Soviet counterparts in Yerevan to share their insights with representatives of the French and Japanese teams. It is hoped that these insights will aid the Soviet's reconstruction program and also serve as the basis for other cooperative endeavors to reduce the chances of a disaster like this one from happening again in the Soviet Union or in the many other parts of the world that are vulnerable to natural disasters.
By Mary Ellen Williams
When Galeras Volcano near Pasto, Colombia, became visibly active in February 1989 after 2 years of intermittent precursor activity, it afforded the perfect site and opportunity for an international workshop on rapid response to volcanic crisis. The imminent potential for disaster was present throughout the training
State of Narino, the city of Pasto, and the Oficina Nacional para Asistencia de Desastres of Colombia.
Prior to the establishment of the VDAP in 1986, the USGS and OFDA had mobilized their responses to volcanic disasters on a case-by-case basis. From those responses to volcanic crises, it was decided that to develop and to maintain a core team of scientists and technicians—VDAP—who could provide rapid response, assessment, monitoring, and training would be a more effective way to reduce the effects of volcanic hazards. Perhaps one of the most important aspects of the VDAP effort is that it assists developing countries to build their own technical institutions and to enhance their own response capabilities before volcanic crises occur.
Galeras Volcano, Pasto, Colombia, May 1989, site of the international volcano workshop. (Photograph by David H. Harlow.)
session (May 8-29, 1989). This workshop, which was originally planned to take place in Arequipa, Peru, gave participants an opportunity for hands-on training during a real crisis. Although the activity of Galeras Volcano had a substantial impact on the local economy, the volcano stabilized, and no mass evacuations were ordered.
The workshop was held to assist in national and local efforts to respond to unrest at Galeras Volcano and to provide training to Latin American countries that were concerned with actions and problems associated with emergency response to volcanic crises. The 50 participants in the workshop came from Argentina, Bolivia, Chile, Colombia, Ecuador, Guatemala, and Peru. A dozen instructors from Colombia, Ecuador, and the United States taught the workshop sessions.
Held in cooperation with the Instituto Nacional de Investigaciones Geologicos Mineras (INGEOMINAS) of Colombia and the Colombia Geological Survey, the workshop was designed as a training activity by the Volcano Disaster Assistance Program (VDAP) of the USGS. VDAP is cooperatively funded by the USGS and the Agency for International Development's (AID) Office of U.S. Foreign Disaster Assistance (OFDA). Additional support for the workshop was given by Unesco's World Organization of Volcano Observatories (WOVO), USAID/ Bogota and Guatemala City, and the
... one of the most
important aspects of the
VDAP effort is that
it assists developing
countries to build their
own technical institutions
and to enhance their own
response capabilities before
volcanic crises occur.
The first week of the workshop was devoted to familiarizing the participants with Galeras Volcano, volcano hazards in general, various monitoring and forecasting techniques, data analyses, and methods of effective civil defense response by means of formal talks, videotapes, and field visits. The participants then were divided into groups to work with INGEOMINAS and public service groups to improve the monitoring and forecasting facilities on Galeras, to define hazards and risks associated with the volcano, and to assist ongoing education, information, and communication activities by national and local governmental and civil defense groups.
The groups specifically addressed the following:
• Hazards evaluations —Geologic field work to determine the nature and distribution of ash, gas, and other eruptive products of past volcanic activity; solicitation and compilation of historical observations; and compilation of meteorologic data that pertain to volcanic hazards.
• Risk assessment—Determination of civil infrastructure and population within the hazards zones.
• Monitoring-forecasting—Seismic, deformation, geochemical monitoring, and upgrading and organizing a computer facility at Pasto Observatory.
• Information-education —Evaluation and development of pamphlets and posters for the public; development of a videotape on volcanic hazards and Galeras Volcano.
During the last week, the working groups summarized their studies and produced reports and other products that could be used by Colombian groups in response to an eruption of Galeras Volcano. These products were also intended to be used as guides in planning responses to future volcano crises in the participants' countries. On the final day, the findings and products were reviewed in a closing conference. Local and national Colombian officials and U.S. Embassy personnel joined the participants and instructors in reviewing the products and discussing the findings. Written reports were submitted to the workshop organizers.
A resolution was also written and signed by workshop participants recognizing the need and giving full support to the formation of the Centro Andino du Volcanologia to assist at Galeras and to provide technical training and support during any future volcanic crisis in other locations in South America.
As a result of the workshop in Pasto, Colombia, VDAP was able to contribute to strengthening the volcano observatory at Pasto. This recently established observatory had been sharing equipment with another Colombian volcano observatory in Manizales. The Manizales Observatory was established with assistance from the U.S. Government during the volcanic eruption of Nevado del Ruiz in 1985. Equipment for the Pasto Observatory has now been augmented substantially by the U.S. Government, and for several months, U.S. technical advisors for VDAP have monitored the volcano with the Colombians. A transfer of this equip
United States Hosts
By Bruce B. Hanshaw
Just over 6,000 earth scientists, exhibitors, and guests representing 104 countries around the world gathered in Washington, D.C., from July 9 through 19 to attend the 28th Session of the International Geological Congress (IGC). The Congress was cohosted by the U.S. National Academy of Sciences and the U.S. Geological Survey, in cooperation with nearly 150 scientific societies, governmental bodies, universities, industrial organizations, and individual sponsors. The United States has hosted two previous IGC's, the 5th in 1891 and the 16th in 1933. Fourteen members of the last U.S.-hosted (1933) IGC attended a reunion with other honored guests and IGC officials. The 28th was the largest Congress in its 121-year history.
The 28th Congress featured more than 3,000 scientific and technical presentations on the latest research in geology, geochemistry, geophysics, and allied disciplines. Also featured were nearly 50
Scientists measuring deformation, Galeras Volcano, Pasto, Colombia, May 1989. (Photograph by David H. Harlow.)