Megaquake and landslide warning for Kashmir in high Himalayas

Megaquake and landslide warning for Kashmir in high Himalayas

Roger Bilham, professor of geological sciences on the University of Colorado at Boulder warns that possible magnitude 9 megaquake, combined with hotspot of potential conflict, could unleash nightmare scenario in the troubled Kashmir region of the Indian subcontinent.

Worse still, Bilham fears that such a major quake is likely to trigger landslides that could dam the Jhelum River, which drains from the Indian-controlled Kashmir Valley into Pakistan. That could put the Kashmir Valley under water within three months - and would also threaten disastrous flooding in Pakistan if the waters were released too quickly.

His new estimate of the largest quake possible in Kashmir comes from 8 years of readings from GPS sensors placed in areas under both Indian and Pakistani control. The work was made possible only thanks to collaboration with both nations, which are in a tense military stand-off over the contested territory.



In this region, the Indian plate is slowly burrowing under the Tibetan plateau. Bilham was looking for where the relative movement of the Tibetan plateau was slowest, as this indicates where compression is building up, and a rupture is eventually likely to occur. He had expected this to be in the Pir Panjal Range, to the south of the Kashmir Valley, but instead it was in the Zanskar Range to the north.

This means that the zone likely to rupture when a quake eventually happens could be 200 kilometres wide, rather than about 80 kilometres, as was previously thought. The zone would encompass the Kashmir Valley - including the city of Srinagar, home to some 1.5 million people. If slippage occurs over a length of 300 kilometres, as is possible, a megaquake of magnitude 9 is the likely result. Given building codes and population in the region, that could mean a death toll of 300,000 people. What Bilham can't predict from his GPS results is when such a disaster might happen.

Bilham points out that seismologists have been caught out by recent megaquakes, including the magnitude 9 Tōhoku quake that hit Japan in March, by basing their estimates on historical patterns, rather than physical measurements.

The state was hit by a 7.6 intensity quake in 2005, with epicenter around Muzaffarabad in Pakistani Kashmir, killing over 100,000 people.

G.M. Bhat of Jammu University, who has undertaken extensive study in seismology, said: "Rough calculations indicate that 'Great Earthquake' happen every 500 years. The records show the last one occurred in 1555 in the Kashmir seismic gap of the Himalayan range."

Bilham has also mentioned in his study that the last "great earthquake" occurred in the Kashmir gap in 1555 and before the next one, a smaller earthquake of 7.6 intensity rocked this gap (in 2005).

"Studying this pattern we can say that a 'great earthquake' can rock Kashmir by or before 2055,"  Bhat said.

The Himalayan zone is divided into three seismic gaps - Kashmir, Central and Assam. Jammu and Kashmir, Himachal Pradesh and Uttrakhand fall under Kashmir gap that falls in the highest risk zone.

Bhat said that during the earthquake in 2005, only one-tenth of the elastic energy under the earth was released. "As nine-tenth energy is still held inside, the 'Great Earthquake' can happen before 2055."

Comments

Dr.B.ramalingeswara Rao, Scientist, NGRI, Hyd 3 years ago



















Fig. 2.12: Seismically active period of 25±2 years from 1816-1839 in North Indian Plate Boundary (NIPB) (dashes) has been observed whereas South Indian Shield (SIS) is inactive during this period for M 6 and vice-versa upto the present (see Table-2.4); Presently, NIPB is in seismically active period from 2001 onwards (modified after Ramalingeswara Rao, 1993)

Table-2.4: List of Earthquakes of M 7.7 & above and M 6 & above in North Indian Plate Boundary and Peninsular India, respectively (as shown in Fig. 2.12) (after Ramalingeswara Rao, 1993)


S # Date Mon Year Lat (N) Long (E) Mag NIPB SIS Reference
1 --- --- 1764 17.90 73.00 6.0 * KEL

2 26.05.1816 30.00 86.50 8.0 * NEPAL
3 16.06.1819 24.00 71.00 8.0 * JK
4 06.06.1828 35.00 77.00 X * OLD
5 26.08.1833 28.00 85.00 X * OLD
6 23.03.1839 21.90 96.00 XI * OLD

7 31.03.1843 15.20 76.90 6/ 5.8 * OLD
8 27.05.1846 23.90 79.00 6.3 * OLD
9 26.04.1848 24.40 72.70 6.0 * OLD

10 09.06.1869 28.00 85.00 X * OLD
11 30.05.1885 34.10 74.80 X * MIL
12 12.06.1897 25.90 91.80 XII, 8.7 * MIL
13 07.02.1900 09.50 76.30 6.0 * BASU
14 04.04.1905 33.00 76.00 8.6 * GR
15 21.10.1907 38.00 69.00 8.1 * BDA
16 07.07.1909 36.50 70.50 8.0 * BDA
17 23.05.1912 21.00 97.00 7.9 * BDA

18 21.04.1919 22.00 72.00 6.3 * TAN
19 02.06.1927 23.50 81.00 6.5 * GR

20 15.01.1934 26.50 86.50 8.4 * BDA
21 12.09.1946 23.50 96.00 7.8 * BDA
22 15.08.1950 28.50 96.50 8.7 * BDA
23 18.11.1951 30.50 91.00 7.9 * BDA

24 10.10.1956 28.10 77.70 6.7 * SRS
25 10.12.1967 17.70 73.90 6.2 * HK
26 30.09.1993 18.07 76.60 6.3 * USGS
27 22.05.1997 23.18 80.02 6.0 * IMD

28 08.10.2005 34.60 73.62 7.6 * USGS
29 24.09.2013 26.97 65.52 7.7 * USGS


It is interesting to note that the occurrence of Muzaffarabad earthquake of 8th October 2005, is inferring the initiation of active period in NIPB again. We may expect M 7.7 number of earthquakes in Himalayas in future, if this hypothesis may be correct.

Is there a Big One is due in Utterkhand?

Large earthquakes are thought to follow a ‘seismic cycle’ as it takes time to accumulate tectonic strain in an area and then release it during a large earthquake. When an earthquake of magnitude over Mw 7 hits some area in the Himalaya, it takes decades for a similar earthquake to hit the same neaby area. Conversely, if no large earthquake has occurred in an area for a long time, the possibility of a ‘Big One’ should be considered seriously. The Indian seismologist, Khattri (1987), and Bilham et al. (1995) have identified one such ‘seismic gap’ in the central parts of the Himalaya (between Kathmandu in Nepal and Dehra Dun in India) (now considered by Bilham’s group in between Srinagar and Pir Panjal region suitable for mega earthquake), which has not experienced a large earthquake over the past two hundred years. Ramalingeswara Rao (1993; see Fig. 2.14 in between 76°E-80ºE in Himalayas), Rajendran and Rajendran (2005) have also discussed status of seismic gap in Himalayas that indicate the central Himalayan frontal thrusts may be undergoing a quiescence of 1000 years in terms of generation of great earthquakes. Assuming a steady elastic strain accumulation by plate convergence, and its simple translation as periodic great earthquakes, such long quiescence may appear exciting. We suggest that the long-term quiescence and the spatial and temporal clustering characterize the distribution of large earthquakes in the Himalaya, is a manifestation of the tectonic deformation associated with a highly evolved fold and thrust belt (see modified Fig. 2.14; Ramalingeswara Rao, 1993). Bilham and Ambraseys (2005) have estimated the average slip rates from historical earthquakes since 1500 permit a measure of the convergence rate between India and Tibet for the past five centuries. Averaged over the entire Himalaya, the calculated rate (<5 mm/ yr) is less than one third of the convergence rate observed from GPS measurements in the past decade (18 mm/ yr). This missing slip of 13 mm/ yr is equivalent to four Mw >8.5 earthquakes that are unlikely to have escaped not in the historical written record. Thus, the missing slip is accommodated either in seismic coupling region (40 km from Himalayan front) of locking slab of collision zones and/ or in unlocked slab. It is highly speculative to assess the earthquake risk in the Himalayas without doing much more efforts in this approach.
A space-time observation is made by Ramalingeswara Rao (1993) for 2400 km length of the Himalayan seismic arc where the Benioff zone is absent. It is clearly inferring from the Fig. 2.14, the great seismic gap in the Kashmir-Punjab region (i.e., 75°E to 78ºE) is found to be quiescent in space and about 600 years in time especially in this area. Hence, this potential region is capable to generate next major earthquake in future either in one or two decades. The slip deficit and maximum credible earthquakes for this region studied by Bilham et al. (2001), and later modified by Bilham and Wallace (2005).


Fig. 2.14: Spatio-temporal variation of earthquake distribution for entire Himalayan Arc. It is inferring the shallow earthquakes of magnitude M 6 have been closed at different times and locations. A queiscience of long period has been observed at 76oN to 79oN, which is falling in the east of Kashmir region and Dehra Dun (after Ramalingeswara Rao, 1993)



Reference
Ramalingeswara Rao, B. (1993). Some Observations on Space-Time Seismicity along the Converging Indian Plate Boundary. 30th Annual Convention and Seminar on “Space Application in Earth System Science”, held at NGRI, Hyderabad, page. 27.
A book on "Seismic activity -Indian Scenario, B.Ramalingeswara Rao, 2015

Munjo 7 years ago

what can we do at individual level to inform our people about this mega earthquake expected to happen in near future. i would request I/NGOs to come forward and do whatever is necessary to avoid major human losses. As far as our government is concerned, it seems that either the said report is not in its knowledge which is being discussed worldwide or is not taking this report seriously as nothing is being done at the govt level to create awareness among public at large or plan for the safety of the people of this area. we have already suffered too much in 2005 EQ and it would be a pity if we dont learn a lesson and get ourselves well prepared for the coming disaster (God forbid).

Muhammad Javed 7 years ago

It is really alarming that GPS results shows that stress is building up at a faster rate. However, as indicated, if slippage occur along 300km length of fault, it would cause magnitude Mw 8.04 earthquake according to Wells and Coppersmith relation (1994). We do not have any any record of a magnitude 9 earthquake in Himalaya. Such devastating earthquake could happen even earlier than 2055 and the regional authorities should be ready for such event by planning and taking appropriate mitigation measures.

Azam Durrani 7 years ago

I am representing a Luxemburg based NGO and working in Muzaffarabad AJK since the 2005 Earthquake. We deal in primary health service since then our daily OPD is 250 patients per day. I would be very interested in future development and warnings so that we can take some precautionary measures. Thanks & regards Azam Durrani CountryHead Friendship International Pakistan

TW (@Azam Durrani) 7 years ago

Ok, sure. We'll keep watching. I'll send you email upfront if we have any developing news.

Post a comment

Your name: *

Your email address: *

Comment text: *

The image that appears on your comment is your Gravatar