Sunday, May 31, 2015

Useful websites for Earthquake data and Weather monitoring

a. IMD gives details on latest quake and also an inventory of quakes in current and previous month here
b. USGS has a huge amount of data on quakes here and you can get details on the latest quake along with a map here
I used these sites extensively during the recent Nepal Earthquakes and I found the quake reports being posted within minutes of the occurrence.
c. You can try this ArcGIS site for some maps and info (Nepal Quakes)
a. IMD has recently updated its website and put in a wealth of information :-
i. It has a ticker where you can register for cyclone alerts by SMS here. I tried registering myself but it did NOT quite work (hope it is a glitch which they will iron out soon).
ii. From this year onwards, IMD has a special weather forecast for the mountainous regions of the Western Himalayas here. While this is wonderful, I wonder when they will have something similar for the Eastern Himalayas as well.
iii. You can get your actual rainfall data etc from the Automatic Weather Stations and Automatic Rainfall Gauges almost on a real time basis here. A word of caution - many stations are not working or give wrong data!
iv. The satellite imagery page has undergone major changes with tons of data which are meant and can be understood only by a meteorologist. However, this is my absolute favorite where you can see cloud movements taking place almost as it is happening! The 'refresh' button updates the timing of the imagery. Please remember these are IR images.
b. It is worthwhile checking the websites of meteorological departments of our neighbours Pakistan and Bangladesh which also have satellite images, as well a host of other data.
c. The US Navy's JTWC is perhaps the best website for tracks of any cyclone/hurricane or typhoons which is also linked to Google Earth.
d. Last but not least you can look up our blog, where you will find the monthly rainfall data for the last four years of many stations in the Darjeeling-Sikkim Himalaya. Also as a part of the 'STH stormwatch' series we publish early/advance warning, tracks and other data on adverse weather phenomenon for this region as soon as we detect it on websites  - which implies that our service is totally internet based and will not function if the network malfunctions.
Comment by Praful Rao
If you know of other websites (and I am sure there must be a myriad other sites) which provide reliable early warning/ data/ information on hazards esp for this region which can be used to save lives, please share the same with us.
Contact us at

Praful Rao,
Dist Darjeeling

Friday, May 29, 2015

Extreme Weather Events1 - 'Weather Whiplash' - Texas floods May2015

They call it ‘weather whiplash’- a year of historic floods, fires, tornadoes, snow and ice where weather shifts from one wild extreme to another.
In Wichita Falls, Texas it felt like the drought ended overnight. In just 3 weeks, much of the state had gone from extreme drought to crippling floods. Lakes are fuller than they have been in five years. Scientists say climate change is exacerbating the wild swings.
‘The swings are getting wilder’, says Katherine Hayhoe, Texas Tech Climate Change Researcher ‘Climate change is stretching out our variability’. In the last 30 days, 2.6 trillion gallons of water have filled Texas reservoirs, enough water to serve California for one and a half years. 

- excerpt from  and

Praful Rao,
Dist Darjeeling

12th International Symposium on Landslides, Naples (Italy)

The theme selected for ISL 2016 is Experience, Theory, Practice.
The symposium will focus on the following SESSION THEMES
The Scientific Committee encourages Authors to submit abstracts dealing with one or more of the following TOPICS
  • Soil and rock properties
  • Investigation and slope monitoring 
  • Mechanisms and mechanical aspects
  • Analysis and modelling
  • Risk analysis, assessment and management
  • Control works
Read more here

Praful Rao,
Dist Darjeeling

Tuesday, May 26, 2015

April 2015 Rainfall Data and the relationship of Fatal Landslides to Rainfall (SW Monsoons)

With the monsoons just around the corner, I thought it pertinent to post two graphs; the centre one is from Dr David Petley's recent blog on the 'Timing of the Landslide Season in Nepal'. The lower graph is from here
Though the graphs are for Nepal and Darjeeling, they undoubtedly highlight the relationship of rainfall to fatal landslides in the Himalayas.

Praful Rao,
Dist Darjeeling

Wednesday, May 20, 2015

Four maps which speak a thousand words...

The USGS is undeniably one of the most authoritative bodies in the world, when it comes to seismic studies. In its tectonic summary of the Himalaya and its vicinity, it states "The northward under thrusting of India beneath Eurasia generates numerous earthquakes and consequently makes this area one of the most seismically hazardous regions on Earth."
Unfortunately, the subduction zone running from Kashmir to Arunachal Pradesh (see map above or pdf file here) passes almost directly below where we live (Darjeeling-Sikkim position in above map is approximate and not from USGS).
In India, the IMD is responsible for seismicity of the region and the seismic map of India with a focus on the Darjeeling-Sikkim region is placed above.
The GSI is the nodal body in the country looking after landslide hazards and as per them, the Darjeeling-Sikkim Himalaya is amongst the most hazardous areas (see above) in the country with regard to landslides.
Dr David Petley is a world authority on landslides and we consider an honour that STH has been featured a number of times on his famous landslide blog
Placed above is his map on fatal landslides in Asia and without a doubt, he states the most fatalities  in the world due to landslides takes place along the ' southern edge of the Himalayan arc' - which is, sadly where we live.

What never ceases to amaze me is how in the face of such stark, cold scientific evidence and the huge spurt in disaster along the Himalayas, we still continue to bury our heads in the sand and think disasters can happen to everyone - except us.

Praful Rao,
Dist Darjeeling

Sunday, May 17, 2015

Nepal Earthquake: Some questions and answers from an expert regarding the 16May2015 aftershocks felt in the Darjeeling-Sikkim Himalaya

On  16May2015, we in the Darjeeling-Sikkim Himalaya felt two aftershocks and after checking their positions in the USGS map, I could not help feeling the 'epicentre' of the aftershocks had shifted eastwards towards us. I posed this question to Dr Malay Mukul of IIT Mumbai; placed below are my questions/statements (in Italics) and Dr Mukul's answers :-

1. Can't even imagine how it must be in Nepal; we in the Darjeeling-Sikkim region felt 2 aftershocks on 16May2015 (centred East of Banepa at 0920h IST and North of Ramechhap at 1704h IST).

Nepal obviously is feeling the brunt of it. Again, for a 7.3 triggered shock one would expect aftershocks typically up to 6.3. For the two events we have had the following:-

Fig 1(above): The epicentral plot of the main events and the major aftershocks associated with the Nepal 2015 Earthquake.
For 7.8 event we had 6.1, 6.6, and 6.7 aftershocks. For the 7.3 we have had 6.3 and 5.7. So far no real anomalies except that 7.8 shock triggered a 7.3 event farther east. The aftershocks associated with the 7.3 event were located near the epicenter of the 7.3 event so nothing abnormal about that. The orange event (Fig 1) was yesterday's aftershock. Pretty much within the cluster. Not suggesting that the rupture is going farther east. At least not yet!

2. What I find disturbing is the fact that the aftershock 'epicentres' SEEM to be moving from west of Kathmandu initially, eastwards towards our area.Which I think you also pointed out in yr last letter (published here). Can this be correct?

Yes! The aftershocks did tend to follow the Main Himalayan fault (MHT) from west to east. However, the map below (Fig 2) shows that apart from the Mirik event (27Apr2015), the earthquakes have been clustered within the area more or less defined by the two 7+ events. So I would say, no evidence of the aftershocks propagating farther east as of now. If aftershocks transcend the East and Central Nepal boundary, we really need to start worrying.

Fig 2: Epicentral plots of the main events and the aftershocks associated with the Nepal earthquake 2015.

3. Without being an alarmist, I do hope our administration and political leaders are aware of the possibilities and consequences should an event take place here- having served in the IAF and worked in disaster management, I believe it is better to overreact in crisis situations rather than not react at all.

I agree that we need to have a realistic disaster management plan in place in our region both in the short and the long term. That is the least we can do in the light of the fact that we have been made acutely aware of our vulnerability to big Himalayan earthquakes by the Nepal 2015 event and future projections of a 8.2 to 8.7 earthquake in our part of the Himalaya (Fig 3).

Fig 3: Darjiling-Sikkim is projected to be vulnerable to a 8.2 decollement earthquake in the future.

Praful Rao,
Dist Darjeeling

Monsoons 2015 progress and seasonal rainfall

Praful |Rao,
Dist Darjeeling

Friday, May 15, 2015

Quote of the Day and two images

"The haphazard construction of buildings scares me. People here love to encroach and have no regard of rules. They don't listen to anything."                                                                                                                                            Shri Nitish Kumar,
Chief Minister of Bihar,
talking at the 1st Bihar Conference on DRR

      Both Gangtok (Sikkim) and Darjeeling (W Bengal) are booming towns in the Himalayas, located in seismic zone IV and also in one of the most landslide prone areas of the country. I wonder whether Shri Nitish Kumar, Chief Minister of Bihar was also alluding to the many townships, all along the Himalayas which are becoming recipes for disasters?                               

Praful Rao,
Dist Darjeeling                                               

Wednesday, May 13, 2015

The 12May2015 Nepal Quake : An expert's view

Dr Malay Mukul of IIT Mumbai (Dept of Earth Sciences) hails from Kalimpong and has contributed numerous articles to this blog. After yesterday's quakes which rattled much of India, I posed him this question :
'What the hell is happening in our region?'
His reply is placed below :-
The 12May2015, 7.3 earthquake in eastern Nepal was not completely unexpected. When we had the December 2004, 9.1 Indian Ocean Earthquake, there was similar 8.6 shock in March 2005. There were also two 8+ events in 2007. So once the beast wakes up, it will take its own time to settle down. We can do precious little to change this except either to get out of the way and live in safer places in peninsular India or, if that is not an option, to live in houses that will not kill us during a great earthquake (magnitude 8 and above).
Today's 7.3 earthquake appears to be identical to the 7.8 event. Same fault plane at almost identical depths. The fault that got active is the basal decollement fault of the Himalaya called the Main Himalayan Thrust. This is a fault that is present at the base of the Himalaya and extends from Kashmir to Arunachal Pradesh. Obviously, it is present below us in the Darjeeling-Sikkim Himalaya too.
All the GPS work people have been doing in the Himalaya tells us how much this fault is slipping per year in different parts of the Himalaya. It was about 18 mm/year in the Nepal Himalaya and looks like it is about 16 mm/yr in Darjeeling-Sikkim.
Imagine a beaker filling up with water at this rate. So the question is when will the beaker completely fill up? Once it does, nature empties it out in an event like the Nepal 7.9 earthquake.After that it starts filling up again.
Two scenarios can arise because of this:
1.The 7.9 event also causes a southward lurch of the Himalaya. In the 7.9 event, the Himalaya lurched south by about 4m at 15km depth which was effectively about 1m at the surface. This lurch would also add strain (or water in our example to the beaker that is filling up nearby)to the whole
system. If this sudden addition causes the beaker to fill up in an adjacent region,another event would occur. Strictly speaking it is not an aftershock and a separate event by itself with its own aftershocks.
However, it is an event that is triggered by the main event.
2. The beaker did not empty completely during the 7.9 event. In that case the beaker simply empties itself in two events rather that one. This is definitely better than having a single bigger event. Two 7+ earthquakes are better than one 9 event!
The aftershocks of the 7.9 event showed that the earthquake rupture was propagating east. In fact today's event was very close to the region where we saw a 6.7 aftershock earlier. Would it trigger an event in Darjeeling-Sikkim? It could, if we think the first scenario was operational.
Yes! I totally agree with you, having an earthquake on the decollement or the Main Himalayan Thrust in the Darjeeling-Sikkim Himalaya would be our worst nightmare. We have been very lucky. Nature has given us three warnings!  September 2011 and the 2015 Nepal events.
All projections seem to point to us and say that we could be next. We need to get our act straight! The NIMBY (not in my backyard) syndrome may no longer be applicable to us!
Comment by Praful Rao

The writing on the wall is writ large and clear.
Increasingly and every year, disasters in and around the Himalayas (hydrological and geo) are taking a huge toll both in terms of human lives and economic losses. Yet, despite 'the three warnings' Prof Mukul talks about or the recent Kashmir and Uttarakhand disasters I am sure nothing much will change and we will continue our 'normal activities' as if nothing ever happened.

Praful Rao,
Dist Darjeeling

Sunday, May 10, 2015

Nepal 7.9R Earthquake (25Apr2015) : 96 Aftershocks (in two weeks) and still counting...

Placed above is a record of aftershocks (source) following the 7.9R earthquake which devastated large parts of Nepal on 25Apr2015. There have been 96 aftershocks till date (including the induced 5.1R quake which was epicentred around Mirik.
In order to generate awareness about quakes especially amongst the people of the Himalayas, I posed several questions to experts.
The questions and answers (in this case given by Dr Malay Mukul, of IIT Mumbai, Dept of Earth Sciences) are placed below :-
Q. Regarding the Nepal quake, why are there so many aftershocks WITHIN a short time frame - 96 within a time span of 2 weeks? The 6.8R (18Sep2011) Sikkim earthquake which we experienced never generated so many aftershocks.
A. This is normal. If you just see the aftershock records for the Bhuj earthquake,you will find that they continued for months after the main shock. You would see is a gradual decrease in the aftershock magnitude as well as number of events. Now we are mostly getting 3s and 4s.
The aftershock activity is also a function of the magnitude and depth of the main earthquake. Shallower and large magnitude main shocks create more intense aftershock activity.
The Sikkim earthquake was much lower in magnitude as well as deeper.
Q. Are the continuous rattling (aftershocks) dangerous for installations and structures already weakened by previous tremors? I know that 2 hydel projects in Darjeeling district suffered some damage during the recent quake.
A. Yes! Aftershocks tend to add to the damage created by the main shock and in many cases topple structures that were still standing at the end of the main shock. So if your building has suffered structural damage you need to make sure you either fix it or stay away from it.


Comment by Praful Rao
My thanks to Dr Malay Mukul for his prompt answers. 

Two major earthquakes have shaken in this region within the last 4 years, (6.8RSikkim and the recent Nepal one), yet we continue to flout all regulations regarding building codes and continue to construct thousands of 8-9storey buildings on these fragile mountains. I also wonder whether the numerous dams that we have constructed or are constructing  are safe?

Praful Rao,

Dist Darjeeling

Thursday, May 7, 2015

Earthquake induced landslides and the onset of the SW monsoons 2015

Placed above is a preliminary map of Earthquake Induced Landslides in Nepal (read Dr Dave Petley's report here). I am aware of a similar study being carried out by a team from the GSI in the Darjeeling-Sikkim region.
With the SW monsoons knocking at our doorsteps and almost 3000mm of rain ahead (for Darjeeling district) in the next 5months, my biggest fear is how our injured mountains will bear up with this onslaught... and don't forget that 'developmental activities' such as road building and construction work including those of dams have gone ahead over the years, at breakneck speed in this entire region, with little regard to the environment.
In this regard, placed below is an article by Ranit Chatterjee, a graduate of TISS and now a student at Kyoto University(Japan):-


In the back drop of the recent earthquake in Nepal followed by temblor in the hills with epicentre located in Mirik and keeping in mind the approaching monsoon season ,the area may get hit badly by landslide in the coming months. The occurrence of earthquakes in steep landslide-prone areas greatly increases the likelihood that landslides will occur, either because of ground shaking or shaking-caused dilation of soil materials, which allows rapid infiltration of water. The second condition is more serious for Darjeeling considering the soil and rock conditions. The Darjeeling area may see an increase in landslides as an after effect of the series of recent earthquakes and onset of rainy season. Interestingly, it has been noticed that the rainfall pattern has changed in the region. The annual rainfall though has not changed much but the rainfall pattern is no longer uniformly spread over five months but happen in concentrated pockets over a short span of time mainly in July and August. This increases the runoff and chances of landslides increases.
In order to increase the level of awareness and preparedness at both institutional and personal level following measures can reduce the risk to a certain extent.  
1. Early warning system especially for heavy rainfall, landslide is an effective measure for saving lives. In the hills due to very spread out settlements it is important to set up a mechanism to transmit message across to villages. The banging of electric poles  can be used effectively to alert people when power supply is down and SMS is not available.
2. Identify safe locations for each area and the knowledge of safe location should be communicated to the community. A general system needs to be practiced where community leaders can guide them to the safe house. Like practiced in Japan once a year a real time mock drill for evacuation may be useful to put down a protocol and understand the evacuation process.
3. In case of houses, which have been damaged in the recent earthquake or aftershocks. It is recommended to get a structural safety check done by a qualified structural engineer or Civil engineer. Architects are trained in design and basics of structures and can handle up to 4 storied buildings unless he or she has a specialization in structures. Draftsman and masons are equivalent to quacks please avoid their advise on design and structural safety.
5.  Check for possible signs of landslides like tilting of trees, fences, and electric poles. Cracks in the lintel and sill of doors and windows.
6. Observe the weather closely everyday on your smart phone or Internet. A good practice is to keep a check on the weather forecast and warnings for the day.
7. Know the emergency contact numbers of the local fire service, police, disaster management department, ambulance etc.
8. Keep important documents inside plastic packet to protect from damage by water. Laminating important document is another of protecting the documents.
9. Preparation of an emergency kit at household level.

Praful Rao,
Dist Darjeeling