Sikkim (2011)-Nepal (2015)-Manipur (2016) Shock –
Earthquake Preparedness Stake
for
NE States of India is Real and Achievable(An advisory)
By
Prof. Chandan Ghosh
NIDM, MHA, Govt. of India
New Delhi 110002
1. Whether another
shock from the Himalaya will shatter our hope to live as long as we are
destined to, is not the issue before us now. Growth in
population, economies, and societal interconnections have led to significant
increases in lives and infrastructure at risk and to ever larger areas affected
by “local” disasters. India is no different from other earthquake prone
countries.
a. Irony
of the fact is that Earthquake hazards and their impacts are still not fully
understood, even after deploying 70000 seismic stations across the world and
analysis of 20000 plus waves (GEM: http://www.globalquakemodel.org/) so far
indexed. The future of the earthquake predictions may not come handy sooner or
later till we are able to comprehend the whole issue as a “system science”. But
what’s important is that every damaging earthquake provides new knowledge about
their nature and how to guard against future losses. Whether India has taken
any good lesson after series of earthquake since 1988 Bihar-Darbhanga, there are
no authentic as well as readymade answers. However, questions are raised after
every earthquake struck in the Himalaya – how much prepared Delhi is? The
answer, is mostly defined in the seismic zonation (say Zone IV in Delhi-NCR) we
belong to and anything beyond that is not possible to specify by any agency or
experts. In this direction, countries
like Japan (after 1923 great Kanto Earthquake), Turkey, Taiwan (after 1999
earthquake), have taken great stride in mobilising earthquake resistant
measures into exemplary practice.
b. Earthquake-related
provisions in building codes have primarily sought to protect the lives of building occupants, with the objective (but
not a guarantee) of “life safety”
. Code-compliant buildings may protect their occupants in future earthquakes
but are not required to be designed to limit economic loss. Similarly, damage
to infrastructure lifelines, such as telephone network, water supply, gas
pipes, electric power transmission lines;
may not cause death or injury, but may result in significant economic
losses and delayed recovery efforts.
Fig. 1: How a building system exists in
our country’s context may be described as the signatures of the past
generations codified in the human genome but reality of their performances are
way behind the technologies proved to be appropriate more than five decades
ago; yet we are not sensitive enough with our duties for the safe constructions
in the country till we expect some Govt. regulations will deem fit for
coherence/compliance (Figure source; http://www.globalquakemodel.org/what/physical-integrated-risk/building-taxonomy/)
Table 1: Records of
last 10 years indicate that felt earthquake (M5 and above) are taking place 4-5
every day and this has been found almost at same trend for the last 120 years
of instrumental records. Therefore, prediction of earthquake, specially by
several non specialists becoming active across the world during aftershock
period, may not improve our understanding of the “panic” situation but we have
to realise that buildings where are staying, they have to have some resilience
to fight against earthquake. Once our earthquake early warning (EEW) systems
are effectively deployed in the Himalaya and receive signals within few seconds
after the occurrence of earthquake, the degree of “panic’ situation (as we
faced during Nepal-2015 earthquake) could be controlled and for that matter
people living in Delhi would have got “visit” information of the Nepal
earthquake atleast 2 minutes in advance (cf. Fig. 2).
Number of earthquakes
worldwide for 2005–2015 (Source: Wikipedia)
|
|||||||||||
Magnitude ranging between
|
2015
|
||||||||||
8.0–9.9
|
1
|
2
|
4
|
0
|
1
|
1
|
1
|
2
|
2
|
1
|
1
|
7.0–7.9
|
10
|
9
|
14
|
12
|
16
|
21
|
19
|
15
|
17
|
11
|
19
|
6.0–6.9
|
140
|
142
|
178
|
168
|
144
|
151
|
204
|
129
|
125
|
144
|
123
|
5.0–5.9
|
1693
|
1712
|
2074
|
1768
|
1896
|
1963
|
2271
|
1412
|
1402
|
1577
|
1305
|
4.0–4.9
|
13918
|
12838
|
12080
|
12292
|
6805
|
10164
|
13303
|
10990
|
9795
|
14941
|
12592
|
Total
|
15762
|
14703
|
14350
|
14240
|
8862
|
12300
|
15798
|
12548
|
11341
|
16674
|
14040
|
Fig. 2: This bullet
train in Japan was stopped during Mid-Nigata earthquake of 23rd
October 2004 by applying automatic brake derived from Earthquake Early Warning
system deployed along the train tracks. Think of the investment made then by
the Japan Govt. for making such system operable vs. savings of life and
properties thereof.
Fig. 3: On December 19, 2011, 8 people killed and 3 injured
in a bridge collapse at Rangchang Khola, about 18 kms from Singtam towards
Dikchu on the Singtam-Mangan highway. The incident took place when a 48-wheeler
heavy trailer carrying transformer of Teesta Urja Project to its project site
in North Sikkim was attempting to cross the bridge span. It was not explained much,
whether this bridge was affected or deteriorated due to Sikkim (18th
Sept 2011) earthquake and if so, what could be the assessment tools to check the
post-earthquake impact on the bridge and many other similar establishments
Fig. 4: Earthquake
Early Warning system architecture in Japan and looking forward to have
something like this in India with the help of central Govt. funding has been on the pure
scientific paradigm for the last couple of years but buying a commercial
product as shown in Fig. 5, is on everybody’s capability but innovating from
the simple ones (Fig. 6) to a more formidable commercial product at our
country’s context could motivate many from creating “panic” atleast during aftershock
period, if not later.
Fig. 5: Earthquake
warning bells available in the market that may not suit ours as we don’t face earthquake so frequently or
we may not find a proper place in the buildings we live, where such bells, if
fitted as per instructions given in the installation guide, may not respond to the “clarion call” because
we hardly can regulate the our building performance during earthquake.
Fig. 6: Indigenised
warning system as above in a common house hold (source: web) that may atleast
wake up people to become “panic” and go out or even start practising
“drop-cover-hold” game! But we have to be cautious and careful, if the shaking,
if at all true, is from earthquake of
near or distant sources. Warning sounds in common house hold as above
manner, created by other non-earthquake yet possible animated objects or pets,
may bring interesting news flux with commotion, which will be much more
confusing yet a good way of awaking people!
2. This
advisory discusses not much about the reasons for
earthquake events in the NE region of the country but by taking into account of
the recent earthquake in Manipur (January 4, 2016) preceded by twin earthquakes
in Nepal (2015), Sikkim (2006, 2011), some imminent steps for the earthquake
mitigation strategy that includes implementation of building codes as well as
facilitation/documentation of good quality construction practices as an
important means to reduces earthquake induced damages and losses.
Therefore, it is important
to take up the following measures by the concerned agencies in the NE states of
India:
a.
Rapid Visual Survey (RVS) of all building stocks as on date by expert
team, to be constituted by each State/capital city/municipalities, which may
include few domain experts from outside of the state. The team may not only
indicate the type of vulnerabilities (not Hazards!) but also prepare some
easily implementable, cost effective, achievable as well as easily trainable
retrofitting/repair techniques to mason/engineers with some field demonstration
(see Fig. 7) of such processes for common public.
Fig. 7: Building as shown above has been marked with several indicative
defects, which are not suggested in the Indian Standard Codes of practices
first published in 1962. Questions are raised why IS:1893 has not been revised
after 5th revision in 2002, but we have to realise that conditions,
such as shear stirrup at 135o at the ends, mentioned in 1962 and
subsequent revisions are yet to be seen in majority of the building
constructions. Therefore, buildings codes are a sort of advisory documents and
community have to take care of such things more importantly than the
regulation/implementation drive to start through designated agencies of the
country.
Fig. 8: If cars are found crashed in this manner under stilt floor for
the very simple yet important lacuna in building construction, it’s high time
to adopt correction measures as described in this advisory.
3.
Identify the soft storey in building (Fig. 8 ) and retrofit them at
least to some extent by filling up some of the selected open frames with full
width brick walls or bracings (Fig. 9) that might not disturb parking facilities.
Fig. 8: Soft storey buildings as above are dotting everywhere as a mark
of modern development. But their performance during Bhuj (2001) earthquake and
many other countries, including Japan, Taiwan; signify that these are deficient
structures. The importance of retrofitting them has appealed many to go ahead
but experiences show that in the name of “jacketing” ground floor columns only,
proper engineering is not ensured. It is rather better to go for selective
“filling up” of open frame/bay at such floors by simple full width brick walls
that may not obstruct parking or other functionalities.
Fig. 9: Measures, such as cross bracings, taken in this building in
Guwahati city has no doubt demonstrated a significant step, which is required
to be documented and advertised for others to follow. Though, there are many
other defects (cf. Fig. 7) seen in the building, the measure taken here is an
eye opener for the earthquake resilient construction.
4. Adopting a new building site, starting from
sanctioning of plans including 4-5 alternative designs with
structural/architectural drawings, estimating costs for labour, materials,
testing, curing etc. as per CPWD or other local rates followed by construction
of the same from soil investigation to foundation to finished super structure
under the complete supervision of a peer review team.
5. LiDAR (LIght
Detection And Ranging) mapping of one pilot area (say 1kmx1km) in a city by an
authorised agency or on PPP mode, demonstrating engineering aspects of
Vulnerability and Risk identification of built up facilities in that pilot area
along with some Non-destructive tools to be used for building health diagnostics.
Based on such information, it’s possible to make a functional Emergency
Operation Centre (EoC), where all operations are to be controlled/monitored and
disseminated.
6.
It may be noted that calling experts from outside and hearing lectures
or organising seminars, teaching students about the basics of earthquake
engineering, giving summar projects to school/college students, training
engineers/architects thru' some central sector scheme (CSS) or even getting
some of the important establishments in the state retrofitted (?) by companies
from elsewhere may bring some
satisfaction in the project managers but not really to the preparedness against
earthquake as a whole and we all know these have been enough so far towards
awareness sans ground implementation.
7.
Therefore,
a.
It's required first to stop unethical construction practices and passing
simple PLAN (not structural drawings!) of buildings. Rather create a body of
experts, who shall make 8-10 alternative plans of buildings along with
structural drawings on a given plot size/shape and do the cost estimate for the
same as per CPWD rates or local market prices so that it becomes a package for
common person to exercise his/her choice at a reasonable set price, which can
be integrated with the normal fee charged for such services.
b.
Identify/map/classify the sources of building materials such as sand,
stones chips, bricks, water, cement, reinforced steel, construction chemicals,
etc. available in the market with respect to standards defined in the BIS codes
c.
Create/identify testing laboratories in the country that would provide
authentication of building materials as per codal specifications.
d.
Create a data base of buildings materials available in naturally and
artificially/authorised/unauthorised sources along with their suitability
criteria as per BIS codes. Mere certification or test report not vetted by
experts under the careful supervision of a peer review team, who shall be
facilitated with creating/recreating test conditions, will not be enough.
e.
State Govt. and corporate need to be motivated to create Building
materials –Shopping Malls, where all the building materials including paints,
construction chemicals shall be marked with barcode/Q-code. Master planners/architects/
engineers/ plumbers/painters/ carpenters/construction workers…land use
registration officers and facilities for training of good construction
practices, retrofitting clinics, etc. may be made available for common public
f.
Create a facility to aid good quality constructions as per
code/guidelines, which are available in the country since 1962!. Create atleast
one Novel example in the locality, where Bar bindings are done as per
structural drawings and performance of the same is tested/demonstrated by earthquake
simulation/shock tests or by computer simulation with virtual earthquakes.
8.
States are encouraged to develop
demonstrative retrofitting projects to highlight the merits of structural and
non structural mitigation measures for:
a.
Retrofitting of (government)
hospitals – at least one in each district
b.
Retrofitting of (government)
schools – at least one in each district
c.
City specific cost-effective retrofitting
solutions for soft storey in a multi-storeyed building.
d.
Promoting for stilt floor parking and
underground spaces in the capital cities are to be dealt with proper
methodology of construction and their supervision.
9.
States are to take up mass awareness
campaigns for seismic risk mitigation by using following means besides ongoing
activities of the respective SDMAs:
a.
Create a Mobile Van mounted with all
instruments and shaking devices to experience the LIVE earthquake with shaking
intensity from I to IX and magnitude up to M7, so that common public are able
to understand the impact of shaking to buildings that they are occupying and at
the same time the science behind the decision making in earthquake measurements
and dissemination protocols maintained by India Meteorological Department. The
same shaking device shall be mounted with seismic base isolators, dampers and
some other anti-seismic measures, so that application of such devices are
understood while controlling earthquake impacts at all intensities.
b.
Create a State/district Museum as
knowledge–hub for the past Earthquakes, keeping repository of information along
with situations and circumstances faced in handling such events in the past so
that new generations are able to recollect past experience, preparedness,
technologies available for risk mitigation.
10.
It may also be noted that earthquake resistant constructions does not
cost more than what people are usually spending/constructing without much knowledge/idea/guidance.
This is an area, where every individual have lots of things to share and modify
the construction scenario, which more often than not, do not qualify to be
worthy exercise towards earthquake resilient practices.
11.
The state/region has to create a proper facility to audit a new construction,
possibly being done by PWD or Municipality or any other private/corporate
agency. In doing so, we shall be able to deal with awareness game that has been
nurtured for the last two decades in the country, much more effectively than
ever.
12.
Buildings in earthquake as well as hilly areas have to be lighter and
stronger, so that they are not damaged much by earthquake induced landslides as
well. The Assam type house (Fig. 10) promoted after great Shillong (1897)
earthquake has not been documented well so far and there is no code available
as on date excepting few articles and publications. States have to organise an
expert team to prepare manual for such building construction that can be cost
effectively produced using steel frame (www.steel-insdag.org/), instead of wooden
frame.
Fig. 10: Assam type house as shown above are mostly one storeyed and these
days they are not affordable. More so technology and knowhow are not documented
for common people. However, steel framed
multi-storeyed buildings are to be promoted in the NE, where pilot studies are
in progress (www.steel-insdag.org/)
Fig. 11: Seismic microzonation of
Sikkim (published in 2006) indicate with RED color about the possible hazards concentration
and so their implications for the possible step to the city planners. How far
such maps have been taken into account, when scores of new buildings in the red
colored area are taking place is to be carefully examined by expert agency.
However, it’s important that State and
national agencies are required to revisit and revise such maps at the context
of damages due to Sikkim (2011) earthquake.
Finally
After
all disaster safety from all natural and man made hazards is the national
agenda as per DM act-2005. Till date we have not only achieved a lot in the
establishment of NDMA, SDMA, DDMAs…NDRF, SDRF in some of the states but also
gained significant momentum in the response and relief operations. Nationwide
mockdrills on earthquake safety, emergency medical preparedness, capacity
building programs, interaction meetings, conferences are conducted at various
sectors in which INGO, UN organizations, NGOs are partners. Main emphasis has
been towards awareness of the people, which is fine and noteworthy effort. At
the same time when we look at the vulnerable establishments in the affected
areas, be it due to cyclone or earthquakes or landslides, the built up
facilities become easy target due to the absence of requisite resilient
measures. Therefore, it is high time to look into protection measures as per
codal provisions given in National Building Code-2005 (being revised in 2015).
The question of taking up the onus by
concerned/designated agencies of the country is not to be asked again and again
or the problem is not going to be solved overnight by framing RTIs or setting
questions to the Law Makers of the country during parliament sessions. What’s
important for the NE states of India, is to revisit the Seismic microzonation
maps (Sikkim-Fig.11, Guwahati, Aizawl, Jorhat, and many more are in progress
under MoES grants) and risk mapping survey conducted so far and incorporate the
findings from these for engineers and town planners to adopt while sanctioning
new constructions. Without facilitating public with good examples of quality
constructions, fighting against the most “uninvited Guest from the Himalaya”,
which is not always cost intensive as it’s thought to be, we can’t make the
country resilient against earthquake and related disasters.
Not sure enough as on today how much
sensitive we have to become on our own by simply remembering Richter Magnitude
or the Zone we fall in and passing over the sensitive information during D-day thru’
social media and getting likes comment any further.
If we still consider earthquake events happening
mostly in the mighty Himalaya, who not only protects us from chill winds but
also reminds us to be prepared enough at safe home we build in using hard
earned money, are just one of the many passing events occupying front page
newspapers, even if once or twice in a year! Then this is not right subject to
talk about and keeping earthquake preparedness as a choice any more. The onus
is not all with regulating agencies but more so with our own pledge to adopt
proven practices of earthquake resilient construction.
For further queries please contact:
Chandan Ghosh, Ph.D. (IIT-K), Dr. Engg. (Japan)
Professor & Head [GeoHazards Division]
National Institute of Disaster Management
Ministry of Home Affairs, Government of India
IIPA Campus, New Delhi 110002
