"Disaster Preparedness and Response: Why is the Phone Off the Hook?" by Ben Wisner. Invited paper for the European Telecommunications Resilience & Recovery Association Inaugural Conference (ETR2A), Newcastle-upon-Tyne, UK, 11-13 June 2003.
Go to: "Same errors recur, despite quake lessons learnt"
by David Alexander.
Go to: Improved building
construction? by James Lewis
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Algerian Earthquake by James Lewis
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Why did they have to die?: No matter how
terrible the earthquake, buildings could survive - if built properly in the first place. back to
Cinna Lomnitz considers the lessons of catastrophe and the
challenge to engineers.
[24 Jun 1999: The Guardian
In the 1985 Mexico earthquake about 400 modern reinforced concrete-frame buildings between
seven and 18 storeys high were destroyed, with up to 472 people killed in one building. It
was the worst in the long history of disasters to have struck Mexico. Comparable seismic
disasters were quite unknown in pre-Hispanic America. The Aztecs lacked the benefits of
modern engineering but their lives were safer than ours. When Professor James Brune showed
some years ago that there is a natural upper limit to seismic ground accelerations, the
Aztecs would just have nodded.
When they felt challenged by nature they tended to do
something about it.
The housing standards of Mexico City, as the Spanish sighted it in 1519, were far superior
to anything then to be found in Europe. The city was larger and better planned than
Madrid. Three causeways linked it to the mainland: the causeways had removable bridges
which made a surprise attack all but impossible. The population was self-reliant as all
their needs were supplied by the lake and by the mud which they hauled up from the lake to
construct their rectangular chinampas or hydroponic fields.
Most life forms tend to adapt to their environment - and earthquakes are part of our
environment. Are we the exception to the rules of creation? It is hard to find another
species besides Homo sapiens which has not learned to make their nests or burrows safe
against earthquakes. It is good to remember that no ground motion as large as 2g has ever
been recorded in an earthquake. But we may easily simulate an acceleration of this
magnitude. Suppose we are riding at 70 km/h and we apply the brakes to bring our car to a
standstill within 20 metres: this test has subjected us and our automobile to a
deceleration of about 2 g. Any car or human should be able to survive this force without
damage. Why can't buildings?
As a 14-year old boy I lived through the great Chile earthquake of 1939, magnitude 8.3,
which killed 28,000 people. Some years later, another catastrophic event surprised me as I
was walking along the fence of Concepcion Airport, some 200km from the epicentre of the
1960 earthquake of magnitude 9.1- believed to be the largest earthquake in human memory.
I felt the 1952 Kern County, California earthquake, magnitude 7.4, while I was a student
in Pasadena under Gutenberg and Richter. I was in Caracas during the 1967 earthquake,
magnitude 7.1 which destroyed a number of 12-storey reinforced concrete-frame apartment
houses sited on soft ground.
I lived through the 1985 Mexico earthquake, magnitude 8.1. It is enough to make me wish
not to have to live through another earthquake. On the other hand, there is something to
be said for having felt damaging earthquakes at first hand.
The human sensory apparatus, imperfect as it may seem to us, remains superior to
commercial seismic instrumentation in some relevant aspects. One type of motion
accelerates the structure in the same direction into which it tilts. This prograde motion
is familiar to anyone who has tried to stand on the deck of a ship. A wave on the surface
of a liquid is prograde, and causes any floating object to move in this fashion. The
opposite type of motion is known as retrograde it impels the object in one direction and
tilts it in the opposite direction.
Charles Darwin described feeling prograde ground motion in the great 1835 Chile
earthquake. He wrote: 'The motion made me almost giddy: it was something like the movement
of a vessel in a little cross-ripple, or still more like that felt by a person skating
over thin ice which bends under the weight of his body.' I too have felt earthquakes on
soft ground. I know exactly what Darwin meant and so did the structures in the recent
Mexico, Loma Prieta and Kobe earthquakes before they collapsed. We shall see that those
three recent disasters have more than a little in common, and there is some evidence that
prograde ground motion could have something to do with it.
Ocean liners are damped, to control rolling and to prevent capsizing. Cars are damped to
control the effect of rough or uneven pavements. Most cars can stand several g's of
horizontal acceleration - more than the most severe possible earthquake can produce. I am
told that no building code in use today could have prevented the disastrous collapses of
modern structures in Kobe or in Oakland.
On the other hand, every single failure was explained in terms of inadequate design or
workmanship. If our building fails it will be our fault. Those structures in Kobe, Oakland
or Mexico City were not made for a soft-ground environment. Charles Darwin could have told
you that. How come our instruments cannot record what Darwin felt? The answer should amaze
no one: we build our instruments to suit our ideas of what we expect to record. We do not
expect the rotational components of ground motion to be particularly important so we don't
record them. Nature thought otherwise or she would not have endowed us with special
sensors for rotational accelerations. These sensors are placed strategically on either
side of the head, in the inner ear. They enable us to feel all three components of
rotations and to tell prograde from retrograde ground motion, as Darwin clearly could. He
was sensitive to the difference because he was prone to sea-sickness, which means that his
inner ear was attuned to prograde motion as found in ocean waves. Sea-sickness is a
defensive response of the nervous system to prograde ground motion.
Consider now norms called 'building codes', and
specifically the earthquake norms. Civil engineering structures such as buildings, bridges
or dams are unique industrial products: they are rarely if ever tested before use.
Detergents, cars, computers, glassware, medicines, even military weapons are tested under
realistic conditions. It seems to me that we don't try hard enough. The potential loss of
life is far greater in the case of bridges, dams or buildings than it is in the case of a
bomber or a submarine. Soldiers go to war fully expecting to be shot at. Civilian families
who purchase an apartment in a reinforced concrete-frame structure because it is
advertised as earthquake-resistant are in a different position.
I can still hear the cries of small children buried alive under the collapsed concrete
structures of Mexico City. There were hundreds of them. In most cases there was no way to
reach them safely and they perished alone in the dark. Sometimes the dying took hours or
days. We have a right to be revolted by such a prospect. Is it the fault of the building
codes, or the absence of standardisation, or the lack of inspection or quality control, or
According to statistics, 16.7% of some 2,000 high-rise structures collapsed in downtown
Mexico City during the 1985 earthquake. Earthquake damage is not God-ordained. It is
cultural in origin. The theoretical peak acceleration in earthquakes - 2g - has never been
actually recorded. There are mass-produced structures, such as automobiles, that can
survive an acceleration of 2g without damage. Therefore it would seem that total
earthquake safety is a reasonable aim. In the 17th and 18th centuries some Mexican
Colonial engineers started to build churches and other large buildings as if they were
ships. Many of these structures successfully survived large earthquakes, including the
1985 earthquake. But the art of building structures as if they were ships has
apparently been lost.
Cinna Lomnitz is a professor of seismology and earthquake engineering at the National
University of Mexico. This article is based on a lecture in London in May at the
Institution of Civil Engineers.
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Ben Wisner, original
RADIX 'think-piece' Back to the top
"As of this morning 39 % of hospitals were lost
and significant damage to laboratory materials has been discovered . Temporary clinics are
being set up to in several areas to accommodate the fact that over 1300 beds have been
rendered unusable by damages caused by the earthquake. In the case of the Rosales and San
Rafael hospitals (see detailed report on the web) damages are structural and will take
years to be fixed." [PAHO, 19 January 2001, see http://www.paho.org]
Since the 1985 earthquake in Mexico City, PAHO has
worked hard to develop with partners in the region methods of structural and
non-structural mitigation for hospitals. These have been published and are available free
of charge. And PAHO experts have been available to assist in implementing this knowledge,
knowledge that is well established. Why hasn't it been used? Why in the year 2001 does
this earthquake knock out 39% of El Salvador's hospitals.
"As usual in Central America, solidarity
displayed by neighboring countries resulted in offers of assistance and the immediate
sending of health professionals, equipment and mobile facilities. Although these mobile
facilities are no substitute for normally operating health services, they are sufficient
to respond to life saving needs. No medical teams, in addition to those from neighboring
Latin American countries and the U.S. Military (SOUTHCOM) are likely to be required.
As a policy, PAHO/WHO discourages sending mobile field hospitals from other than the
closest of geographical neighbors sharing the same culture and health approach, because
they are costly, difficult to transport and arrive too late to make a difference in terms
of saving lives. The high cost of this type of aid (which also quickly depletes
the donor's budget) would be better invested in medium-term needs that often go unmet once
public attention wanes." [PAHO, 14 Jan. 2001, my emphasis]
How well is this policy generally accepted-
Implemented? Does the U.S. Military share "the same culture and health approach"
in PAHO's definition?
"Dr. Claude De Ville, head of PAHO's Emergency
Preparedness Program, pointed out that earthquakes have a profound health effect on the
population. He urged citizens not to rush to bury the dead before identification, adding
that 'while the presence of dead bodies is unpleasant, the cadavers do not cause disease.'
Much more worrisome is the damage to the mental health of the survivors, who may suffer by
not knowing if a loved one is missing or dead, he added." [PAHO, 16 Jan. 2001]
PAHO and WHO have been trying to overcome the myth
that corpses are extreme health hazards for years and years. Why is this myth so
SUMA, the Humanitarian Supply
Management System, Makes Novel Use of the Internet in El Salvador Earthquake
"El Salvador's National Emergency
Committee (COEN) has activated the country's national SUMA team, whose members are among
the more than 2,000 professionals trained in Latin America and the Caribbean. The team is
setting up the SUMA system (www.disatser.info.desastres.net/SUMA)
at anticipated points of entry of international aid to sort inventory and classify
incoming humanitarian relief. At the request of El Salvador's government, PAHO and
FUNDESUMA, the NGO that manages SUMA's logistical operations, sent a support team from
Costa Rica to help in what is expected to be a major operation.
"The earthquake in El Salvador marks
the first time SUMA has used the Internet to alert disaster-stricken countries about what
is on the way. The Government of Colombia (whose national Red Cross Society helped to
create the SUMA system and has been one of SUMA's strongest supporters in the Americas)
has advised PAHO/WHO that they are using one of SUMA's specialized modules - the warehouse
module - to register donations being collected by the Colombian Red Cross and Caracol, a
local radio and TV station. Colombia will use the Internet to forward detailed information
about their shipment to El Salvador's SUMA team, in advance of its actual arrival.
"Similarly, the National Emergency Commission in Honduras (COPECO) has activated its
national SUMA team to register data on emergency supplies being collected at appointed
locations, in coordination with the Red Cross and the Fire Department. As the supplies are
en route to the neighboring country of El Salvador, Honduras' SUMA team also will have
sent an advance report by Internet. This pattern of sending information on donations
before the supplies actually arrive, using SUMA's standard software and criteria for
classifying and assigning priorities to the supplies, will greatly aid the recipient
country by allowing them to get the most important and urgently needed aid to those who
need it quickly.
"FUNDESUMA is also mobilizing additional volunteers from the Dominican Republic,
Venezuela, Honduras, Nicaragua, Colombia and Panama to support the team in El Salvador.
The Governments of Honduras and Peru have also included SUMA trained experts in
their bilateral assistance to El Salvador." [PAHO, 16 January 2001]
There exist excellent technical people and systems in
Latin America (recall Steve Bender's comment at FEMA focus group): engineers, geologists,
geomorphologists, social scientists, public health and emergency physicians, etc., etc.
Why can't this level of expertise be mobilized and effectively USED BEFORE a disaster,
that is in prevention and mitigation - protection of schools, hospitals, critical
lifelines, buildings? Both the building housing El Salvador's emergency commission and the
offices of the El Salvadoran Red Cross were seriously damaged (recall observations of
poorly constructed building where Red Cross delegation in Guatemala's second city,
Quetzaltenango, was housed!).
"A 30-strong rescue team from Taiwan had the area
sealed off and used sophisticated equipment to detect the slightest sound that would
indicate a survivor." [APF, 17 Jan., 2001]
Global Disaster Information Network GDIN Assistance to
"The Government of El Salvador requested assistance from GDIN-International www.gdin-international.org and within an
hour, the organization began organizing assistance. At the request of GDIN, USG remotely
sensed products should be posted up today. In addition, GDIN has requested help from the
European Commission, the European and French Space Agencies, Spot Image and Space Imaging.
ArcInfo has also provided assistance through GDIN. GDIN facilitated products come from
many sources and will be posted on ReliefWeb. "
[Larry Roeder, Executive Director, GDIN, 15 January 2001, see http://www.state.gov/www/issues/relief/gdin.html
This is probably useful in damage assessment in a
situation where transportation is difficult and there are many isolated rural hamlets.
But, again, why is there is advanced technology applied AFTER the event, as with the
medical inventory tool above, rather than as an aid to prevention? Does GDIN have access
to images that would be of assistance in identifying landslide hazard? (See Landslide...
is not Rocket Science.)
"450 people are confirmed dead in Santa Tecla.
The town was founded in 1854 with the aim to build a new capital outside the zone of San
Salvador's frequent earthquakes." [ACT, 16 January
Historical knowledge and historical irony! What about
the one radio news mention of allegations that "rich" people were illegally
harvesting trees from slope above Santa Tecla? Were the trees protected? Since when? Who
was responsible for enforcement? Knowing vs. doing!!
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Haresh Shah recalls
his 1999 email discussion ( email@example.com)
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Thank you for your communications on El Salvador. I share your frustrations and feelings.
After every event, whether it is in the developed world or developing world, we hear the
same excuses and same expressions of "surprises". It seems to me that the
societies at large have become very elastic. They keep taking in these excuses and
"explanations" without breaking. Intellectuals keep talking, professionals keep
meeting in conferences and workshops and what not, and the killing, misery, pain,
disruption, keep happening with unfortunate regularity. What can we do? We cannot give up
or get frustrated or point fingers. We must do what we can.
There are many, many ways in which we individually and collectively can help.
Besides the mailing list you have, I am also sending these communications to WSSI, people
involved in US-Japan programs, a new alliance formed in Tsukuba, etc. I am also attaching
herewith my communications with all of you after the Turkey, Greece, and Taiwan
earthquakes. What I said almost a year ago still is valid. We all need to do something
that will make a difference. Let us keep this dialogue going.
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Landslide Hazard Identification isn't Rocket
Science! Ben Wisner Back to the top
...[R]escue crews reported pulling out four other
victims from a truck swept away by a land slide along Guatemala's stretch of the
Pan-American highway. Other people aboard the truck were listed as missing.
Authorities said 16 separate landslides had cut off roads around Guatemala and that at
least 30 houses were destroyed or damaged in Jutiapa department when the earthquake hit at
11:33 am (1733 GMT) Saturday. [AFP, 14 Jan. 2001]
Landslides seem to be responsible for many deaths in
El Salvador (200 homes buried in one location, 500 in another). Landslides following
earthquakes are very common in Central America. Wouldn't it be relatively easy to identify
areas along major transportation corridors (e.g. OAS trade corridors project) and also in
towns and cities where hazard of landslide is high? Aren't there straight forward things
that can be done to stabilize slopes, or, if not, then shouldn't people and critical
facilities be relocated? This isn't rocket science.
"Landslide hazard mapping is not difficult and
some has been done. We are trying to organize a project around the CA Pan American
Highway." [Steve Bender, OAS, responding to Ben's mailings]
"Just outside the capital, workers dynamited
massive hillside boulders to prevent them from crashing on the roads, several of which,
including one major highway, reopened late Tuesday." [APF, 17 Jan. 2001]
Landslide hazard identification and mitigation, albeit
crude. Why couldn't something of this sort have been done BEFORE? Among all the kinds of
microzonation work that can be done BEFORE an earthquake, identification of zones subject
to extreme landslide hazard must be among the easiest and most certain.
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landslide hazard and risk identification and remediation
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by David Alexander, University of Massachusetts at Amherst
To begin with, nothing reliable can be said about the
landslides caused by the El Salvador earthquake until there is firm information on exactly
what type of movement is involved (Varnes or other classification).
Secondly, landslide identification is, I venture to say, NOT a particularly difficult
task. Most landslides occur in well-defined areas (e.g., stream headcuts). Many are
reactivations of previous movements, or at least occur on slopes where one can detect
signs of other movements in the past.
Pause for a brief anecdote: last July I went down to the regional air photo archive with
the engineer from our local town hall. I showed him that under our town's middle school
gymnasium there were signs of past landsliding (a hint of a degraded, curved scar on a
slope undercut by a stream channel). Yesterday I heard that the brand new bypass around
town will not open this week because immediately after being built it has become affected
by landsliding. It passes under the middle school gymnasium. I have not yet been to see
whether my prediction has been borne out (weariness and discouragement on my part, not
lack of interest!).
The moral of this is that you can probably make quite a good prediction of where
landsliding will occur by looking at reasonably sharp, black-and-white, panchromatic,
stereographic aerial photographs printed at scales of 1:15,000 to 1:25,000, of the kind
that any modern Zeiss repeating air photo camera will take (and, of course, you must make
field visits to verify what you interpret). The cost of a sortie is usually about $10,000
per 150 sq. km, though it varies substantially (aircraft take-off costs are the main
part). After that, you need nothing more sophisticated than the pairs of air photos ($10 -
15 each for 25x25 cm prints), a pair of stereo goggles ($19.95), a fine-point marker pen
($2.49), reasonably accurate contour maps (preferably at 1:10,000) and a few sheets of
clear plastic. Of course, if you can also monitor some sites with piezometers and
inclinometers, your results will be more accurate, but this probably will not add much to
Landslide identification on aerial photographs requires (a) knowledge of the local
lithology and what the terrain consists of and looks like, (b) consideration of texture,
tonality and morphological signs that indicate potential landsliding, and (c) experience
of the local and general scenarios of landsliding. Ceteris paribus, mottled terrain
(signifying disturbed ground) and dark tones (signifying concentrations of groundwater)
indicate a landslide hazard. Slope undercutting, oversteepening or incision, lithological
junctions (e.g., clay abutting limestone at the surface), the presence of springs or
seeps, and variations in vegetation (e.g. presence of hydrophytes such as canes, which
colonize areas of high soil moisture) all indicate landsliding. Cuspate or lobate forms,
headscarps, lateral shears, median trenches, and bulging ground, in either fresh or
degraded form, are all indicative. The investigator needs to have in mind the
characteristics of different types of movement (slides, flows, topples, falls, glides,
Sackungen, rock avalanches; movements of rock blocks, sediment, earth, debris, mud; simple
and composite types, etc.).
Other remote sensing methods of landslide identification are of dubious value. In general,
landslides cannot be identified reliably on satellite images. Even color air photos tend
to be less effective than black and white ones. With the exception of liquefaction
phenomena, most earthquake-induced landsliding is merely a matter of bringing forward in
time, and possibly increasing in size and intensity, what would have happened in the
absence of seismicity. It means that a whole suite of mass movements that would have
occurred in any case (but separately) all happen together. Single earthquakes of M>7
can trigger 10 - 15,000 landslides, though not necessarily all at once, as some of them
may occur within four days of the event as a delayed reaction because pore water pressure
can take time to increase.
Earthquakes with heavy or persistent rain increase landslide potential. So do clastic
sediments and thick soils on deeply incised terrain. The frequency of landslides increases
with a roughly exponential function towards the epicenter, and the main concentration will
occur within a radius of about 30 km.
Liquefaction is a special case, that is more closely
associated with seismicity. Liquefaction potential can be predicted in advance of
earthquake activity on the basis of knowledge of sediments (but in three dimensions, not
just the surface pattern of deposits) and groundwater conditions. Lenses of sand within
impermeable clays are particularly susceptible to liquefaction failure. So are clastic
sediments arranged in alternating permeable and impermeable layers. The latter condition
can give rise to lateral spreads-landsliding at very low angles - which is especially
damaging if it carries along large (or giant) blocks of rock (e.g. olistoliths).
Slope stabilization is not a particularly mysterious process. If it is properly chosen and
established, vegetation can bind soils together and reduce soil moisture content. But not
all vegetation types are effective and some shallow-rooted trees can stimulate mass
movement by blowing over in high winds (hence post-hurricane landsliding). Deforestation
does increase the rate of landsliding, often by various orders of magnitude, but not
automatically, because it also depends on other factors, such as what vegetation or land
cover replaces the forest, what degree of weathering has taken place, what the slope
drainage conditions are, whether the slope is steepening and lengthening, and how fast all
these variables change.
Apart from revegetation and simple surface drainage works, most slope stabilization
measures are expensive. Nets, flexible barriers, rock bolts, gunnite, terracing, deep
drainage wells and channels, debris stilling basins and weirs, osmotic and cathodic
electrical soil moisture reduction systems, pumps, excavation and regrading - they are all
costly and can only be applied sparingly. At least one third of the cost will go in
maintenance and operations - perhaps even two thirds.
Non-structural measures are cheaper and better than structural ones. It is easy enough to
do a regional evaluation (nice if it is on a GIS) of factors That relate to landslide
hazard (lithology, slope angles, lengths and orientations, vegetation and land cover,
anthropogenic factors, etc). In the past it has taken me, working on my own, about a month
to do this by hand for about 150 sq km, with no aids like GIS but with high accuracy. The
end product is usually a regionalized map or rasterized matrix (perhaps with 1 hectare
cells) of landslide potential categories from 0 to 4, which can be contoured if necessary.
Landslide risk requires - that the landslide potential map be crossed with maps of human
habitation and land use. To do this meticulously is time-consuming and involves juggling
with a variety of debatable assumptions about how vulnerability and hazard interact with
each other, site by site. Nevertheless, it can be done quite effectively. Last year I did
it for nine villages and towns in Umbria Region. The key is to look at past history of
landsliding and use this to develop scenarios of what will happen in the future. In this
particular field the past is truly the key to the present.
Carrara, A., Cardinali, M., Guzzetti, F., and Reichenbach, P. 1995. GIS technology in
mapping landslide hazard. In Carrara, A. and Guzzetti, F. (Editors), Geographical
Information Systems in Assessing Natural Hazards.
Kluwer, Dordrecht: 135-175.
Carrara, A., Guzzetti, F., Cardinali, M. and
Reichenbach, P. 1999. Use of GIS technology in the prediction and monitoring of landslide
hazard. Natural Hazards 20(2-3): 117-135.
Cruden, D.M. and Varnes, D.J. 1996. Landslide types and processes. In Schuster, R.L. and
Turner, A.K. (eds) Landslides: Investigation and Mitigation.
Special Report, Transportation Research Board, National Academy
of Sciences, Washington, D.C.: 36-75.
Drennon, C.B. and Schleining, W.G., 1975. Landslide hazard mapping on a shoestring. Proceedings
of the American Society of Civil Engineers, Journal of the Surveying and Mapping Division
Harp, E.L., Wilson, R.C. and Wieczorek, G.F., 1981. Landslides from the February 4, 1976,
Guatemala earthquake. U.S. Geological Survey Professional Paper
1204A, 35 pp.
Lazzari, M. and Salvaneschi, P. 1999. Embedding a
geographic information system in a decision support system for landslide hazard
monitoring. Natural Hazards 20(2-3): 185-195.
Leroi, E. 1996. Landslide hazard-risk maps at different scales: objectives, tools and
developments. In Senneset, R. (ed.) Landslides. Balkema,
Parise, M. and Jibson, R.W. 2000. A seismic landslide susceptibility rating of geologic
units based on analysis of characteristics of landslides triggered by the 17 January, 1994
Northridge, California earthquake. Engineering Geology 58(3_4):
Sidle, R.C., Pearce, A.J. and O'Loughlin, C.L. 1985. Hillslope Stability and
Land Use. Water Resources Monograph Series, Vol. 11, American Geophysical
Union, Washington, D.C., 140 pp.
Veder, C. 1981. Landslides and Their Stabilization.
Springer-Verlag, New York, 247 pp.
David Alexander: Why don't we write an international standard on
disaster mitigation and preparedness?
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