Earthquake Resistant Structures of Himalayas
By DP Agrawal and Manikant Shah
Wednesday, 21 February 2001
Earthquakes don’t kill; badly built houses do. Though this is a time-tested
lesson, it is often forgotten soon after an earthquake. Already, lessons of
the massive January 26 quake that ravaged Gujarat are being forgotten. But,
quakes are not new to India as 55% of the country is prone to seismic shocks.
Several earthquake prone regions in the country have traditionally built houses
that minimize the damage to life and property and stand up well when the quake
hits. These techniques are based on traditional material that have been used
to build such houses—timber and bamboo, for example. The traditional wisdom
and attention to detail can be applied to modern materials as well.
No building can remain entirely free of damage during a quake; still, all houses,
big or small, can be made safer. Structures can be made to withstand earthquakes
of a particular magnitude by taking certain precautions. Buildings collapse
as a result of inertial forces. During an earthquake, the lower part of a building
tends to vibrate as it is in direct contact with the ground. The forces of
inertia, however, keep the upper portions static. This conflict of forces leads
The magnitude of these forces is directly proportional to the weight of the
building—the heavier the structure, the greater the damage. If the structure
is light, fewer people die if the structure collapses. Avoiding compression
structures like domes, vaults, and arches is another option, according to architect
Das Gupta. The structural system needs to be tensile and the material should
be flexible, as is the case with timber, steel and bamboo. It also helps if
the structure is constructed in a way that it vibrates as one unit and sways
together. Traditional constructions in India’s Northeast follow this principle
as do the tall sky scrapers of Tokyo. One can even see their swaying during
a strong gust of wind.
At 2:53 am on October 25, 1991, a moderate earthquake measuring 6.6 on the
Richter scale affected more than 425,000 people of about 2,100 villages in the
districts of Uttarkashi, Tehri, and Chamoli in Garhwal Himalayas in the hill
state of Uttaranchal. Traditionally built timber houses proved to be the most
effective in keeping damage at bay. It would, however, be incorrect to say
that the old-fashioned houses survived just because of the materials used.
The construction techniques, too, determined the amount of damage.
Most new constructions with heavy roofs (slate tiles or RCC) supported by weak
walls (random rubble in mud mortar) proved deadly. Older houses at higher elevations
have timber roofs held together by timber ‘tie-bands’- horizontal timber beams
spanning across the entire building, connecting the entire structure and giving
it the character of a cage. Such houses suffered little damage despite the
Quake resistant houses should have tie-bands just above the level of the floor,
the doors, the windows, and the roof. Corners are the most vulnerable and
ought to be strengthened. Elasticity of the structure can be enhanced with
flexible steel rods or wood batons at corners. Doors and windows should be
few, small, and symmetrically placed away from the corners. The house should
be as light as possible.
All houses designed by the renowned architect Laurie Baker remained intact
during the 1999 Chamoli quake. Baker emphasizes using local construction material
and traditional wisdom.
In a recent paper, Saklani et al (1999) have tried to bring into focus the
old quake-resistant traditional architectural design of the huge multistoried
building constructions found in the Garhwal Himalayas. The Garhwal Himalayas
representing a mountainous zone on the northwest of India constitute a portion
of the great Central Himalayan region, which is known for high seismic activity
and therefore the presence of such structures here is of remarkable occurrence.
The authors report building structures, five to six stories high in the region,
that have endured the ravages of time, weather, and geo-activity for hundreds
of years. The authors refer to the Yamuna and Bhagirathi river valleys in the
Garhwal Himalayas, where these multistoried constructions are locally known
as Sumer, Chaukhat or Kothi. These structures have withstood
a number of earthquakes, including the recent severe ones in 1991 and 1999.
The indigenously devised building technology used to erect Sumers makes
use of locally available resources such as long thick wooden logs, stones, slates,
and clay to specification. Typical Sumers stand 15 to 17 meters
above the ground level and have 5 to 6 floors, with four rooms on each floor.
The ground area covered by the Sumer is 8, 6.5 meters. A foundation
trench 3 meters deep and 70 cms wide is first dug and then refilled with flat
dressed stones. This foundation is then raised above the ground in the fashion
of a rectangular platform, to the height of 2.30 meters with the help of flat
stones, clay and stone fillings. The structure of the Sumer rests
upon this platform. To raise the walls, double wooden logs are placed horizontally
on the edge of the two parallel sides of the platform, which are opposite to
each other. The width of the logs determines the thickness of the walls, which
is 70 cms. On the other two parallel sides the wall is raised with well-dressed
flat stones to the surface level of the logs placed on the other two sides.
The walls are further raised to 30 cms by placing heavy, flat, dressed stones
upon the wooden logs on the two sides and by placing another pair of wooden
logs upon the stones on the other two opposite sides. The four walls of the
structure are thus raised using the wooden logs and dressed up flat stones alternately,
up to a height of about 17 meters. The structure is further reinforced with
the help of wooden beams fixed alternately that run from the middle of the walls
of one side to the other, intersecting at the center. This arrangement divides
the Sumer into four equal parts from within and provides for joists supporting
the floorboards in each floor of the building. On the fourth and the fifth
floors the Sumer has a balcony, with a wooden railing running around
on all four sides. The fourth floor is also provided with a toilet cum bathroom
on the balcony. Specially designed wooden ladders provide access to the different
floors, which are located within the Sumer. The roof of the Sumer
is laid with slate stones.
The Sumers are ascribed to the Rajput families inhabiting the area in
the past who built these to function as watchtowers and to provide for the defense
of all the families living in an area.
The authors point out that structures comparable to the Sumer, with
some variations have been reported throughout the Himalayan-Karakoram earthquake
zone which includes India, Pakistan, Afghanistan and Nepal. They emphasize
upon the need to carry out further research in this regard so that the technology,
with some modifications to suit the present day resource base, could be utilized
advantageously in the seismic zones that hold portents of disaster in the near
We were a bit intrigued as to why such structures were allegedly made only
as watch towers for the defense of the village. This innovative building
technology was good for any house to withstand the vagaries of nature and earthquakes.
We undertook a field survey of such buildings in the upper reaches of the Ganga
and Yamuna valleys.
We found several multi-storied structures in the Yamuna and the Ganga valleys
in Uttaranchal. These structures are peculiar to the traditions of the area
and have been found to be resistant to earthquakes. Such multi-storied, typical
old building structures in the area are indeed remarkable for their high rise
structures that are still intact in this mountainous zone characterized by high
seisimic activity. We found that this peculiar building technology was applied
widely and extensively in the case of all the old building constructions whether
they were single storied, double storied or taller. The spread of the area
where such constructions occur encompasses the entire Yamuna valley but is more
predominant towards the west of the valley.
The words used in local dialects for such structures are Kuda, Thaat, Pherol,
Chaukhat and Sumer.
Kuda refers to a house or a dwelling unit of any kind
Thaat is the dwelling unit dedicated to a deity
Pherol refers to the horizontal wooden beams used alternately with stones
to raise the walls of a structure; the use of this term is however restricted
to the Taknor (Harsil) area in the north Ganga valley of district Uttarkashi;
in the Yamuna valley the same is known as Chhapa – Jor
Chaukhat refers to the buildings in the area that have been built with
the peculiar technology that concerns us here
The word Sumer has often been mentioned in the reports as having reference
to the Chaukhats, but we could not find much tenable proof of such reference
in the local usage; however, it cannot be denied that constructions may be called
Sumer in areas other than the Yamuna valley; we therefore think that use of
the word Chaukhat is most appropriate for our present concerns
The technology applied on the Chaukhats itself is reminiscent of a machine
stitch on a fabric that keeps a piece of cloth in shape. In like manner the
technology makes use of wood, like a thread and keeps the entire structure intact
against the ravages of weather and geo-activity. Though heavy and flat stones
are used, wood predominates the structures of whatever the dimensions are.
Technology used in the Chaukhats
Pairs of thick wooden logs, beginning from the base of any two opposite walls
are used at every 30 inches alternately with heavy stones to raise the walls
and run to entire length of each of the wall
At the right angle where any two walls meet, the edges of the pair of logs on
one wall are placed on the edge of the logs of the other and they are joined
together by hammering thick wooden nails through them; this has an effect of
turning the structure into a single piece construction
Any devices used for windows, doorways, ventilators or floor- joists are joined
to these well-secured pairs of logs, which further strengthen the structure;
the use of pairs of logs gives to the wall a thickness of almost 70 cms
Such time-tested technologies for building quakeproof houses are available
in the Himalayan region. When half of India is quake-prone, this building technology
should be given due consideration in designing quakeproof housing in such seismically
Bilham, R., V.K. Gaur and P. Molnar. 2001. Himalayan seismic hazard.
Saklani, M. Pradeep, Vinod Nautiyal and K.P. Nautiyal. 1999. Sumer, earthquake
resistant structures in the Yamuna Valley, Garhwal Himalayas, India. South
Asian Studies 15: 55-65.