By Dr. Afroz Ahmad Shah
Kashmir already reeling under a deep man made crisis since August 5, 2019 is now faced with a natural calamity. An earthquake of magnitude (Mb 5.9) struck Pakistani side of Kashmir on 24th of September 2019 resulting in more than 20 fatalities. Since fault lines do not follow political boundaries and instead link the two (or multiple) geographically and politically distinct regions into one.
The preliminary investigation of the seismological data suggests that this earthquake has ruptured a fault at a depth of ~10 km. This could mean that the fault has broken a portion of the Main Himalayan Thrust System that runs under Jammu and Kashmir region. This revives the tragic memories of the devastation caused by the Mw 7.6 earthquake on 8 October 2005 in northern Pakistan and Kashmir region which consumed more than 80,000 people and left a trail of devastation behind.
What causes earthquakes in India and Pakistan
The Main Himalayan/Frontal Thrust (MHT/MFT) is the surficial expression of the megathrust fault where an abrupt topographic high marks the end of Indo-Gangetic plains and the start of frontal mountain ranges (Figure). This fault system, which is younger than the other faults systems north of it, remind us of the continuous push of the India tectonic plate against the Eurasia plate that has resulted in the formation of series of faults including the megathrust fault since eocene time. The occurrence of earthquakes in this region is a result of this push that deform rocks and therefore accumulate strain over the geological past that eventually overcomes the strength of these rocks by nucleating fractures which becomes fault and trigger earthquakes.
Most of the present-day earthquakes are reported on the frontal fault system, with some on the interior faults as well. Some of the prominent earthquakes that are associated with significant damage are: the 2005 Kashmir earthquake (Mw = 7.6), the 1905 Kangra earthquake (Mw = 7.7), the 2015 Nepal earthquake (Mw = 7.9), the 1934 Bihar-Nepal earthquake (Mw = 8.1), the 1879 Shillong earthquake (Mw = 8.1), and the 1950 Assam earthquake (Mw = 8.4). The measurement of interseismic strain is therefore one of the most important aspects to understand the seismic hazard to millions of people who live in the closer vicinity of this deadly fault system.
Facing potential earthquake disasters
Undoubtedly, a large portion of population in Pakistan, India, Nepal, Bangladesh, Myanmar, Thailand, Malaysia, and Indonesia live on or nearby active fault systems. Unregulated urbanization, coupled with many folds increase in populations, particularly in the last few decades have put these regions at greater earthquake risk.
Indo-Gangetic plains in India abruptly rise at the foothills of Himalayas where Himalayan frontal fault system emerges at surface at certain regions but mostly runs blind. A series of devastating earthquake in the past are a reminder that earthquakes have greatly shaped the landscape and its history, and often some of the major or devastating earthquakes are recorded in the historical text. Surprisingly during the earlier periods of human settlements, including the latest British India, no standard seismic building codes were enforced or implemented. Past records show that during the later stages of British India seismic resistant building codes were planned after the devastating 1935 Quetta earthquake in Balochistan. Similarly, strengthening techniques are reported to have been implemented after the 1941 Andaman Islands earthquake.
It is important to note that Greater India achieved independence from British rule in 1947, but at the cost of regional instability that was marked by one of the most bloody partitions in the world. The entire region was torn on religious lines with the creation of Hindu dominated India and Muslim dominated Pakistan (both East and West Pakistan at that time). What is more, the seeds of partition sprouted again with the emergence of East Pakistan now on ethnic lines, into an independent nation, called Bangladesh. During this time these newly created nations witnessed deadliest riots, bloodshed and devastating wars. Therefore, any previous effort of planning or implementing of the earthquake resistant building codes, as was done in Quetta, got delayed. This clearly suggests that political stability of a nation is paramount to its preparedness to face any kind of disaster. This perhaps explains why India, Pakistan, and Bangladesh have been unable to achieve objectives to safeguard their populations from disasters even after seven decades of their independence from colonialism. All these countries are still struggling to get out of the debris of partition to implement seismic code.
Unfortunately, it takes a devastating earthquake to research, plan, and implement strategy to counter future potential disasters. This was apparent in most of SE Asian countries after the deadly event of 2004. In Pakistan, the huge loss of life and property that followed the 2005 Kashmir earthquake reminded authorities that there is a serious need to address this issue. Likewise, in India the “Republic Day” earthquake of January 2001, which devastated Bhuj (Gujarat) with more than 19000 casualties did shake the conscience of political class but soon the enthusiasm withered away. After 2001 earthquake both authorities and scientists did kick start a comprehensive planning to understand the causes of earthquakes, and to plan and implement the seismic resistant building codes and earthquake education at large. The National Information Centre of Earthquake Engineering was established, and with it a widespread 4-year National Programme on Earthquake Engineering Education that is implemented at Indian Institutes of Technology and the Indian Institute of Science, developed a large scale education and training framework in India. However, a large portion of work remains to be achieved, particularly in rural areas where implementation of strict building codes is not practiced.
Pakistan which shares a similar political background like that of India, rests on geological structures, and some of them are active and capable of producing deadly earthquakes. It was the devastating Quetta earthquake of May 30th 1935 that caused a large scale damage in Quetta, and resulted in 60,000 casualties. This perhaps forced the British authorities (who controlled it at that time) to enforce strict building codes, Quetta Building Code, and it was subsequently adapted in 1937. The construction of unreinforced masonry buildings was forbidden. This standard practice is reported to have saved people and property during the 1941 earthquake. After independence from British in 1947, British India was torn into Pakistan and India on religious lines, resulting in low intensity conflict between two sovereign nations over Kashmir. This conflict consumed scarce resources of the two nations and explains the delay in preparation and implementation of seismic resistant building codes in these regions. After a period of relatively calm political atmosphere Pakistan developed 1986 Pakistan building code, which however had many problems, and did not reflect the ground realities, and even earthquake hazard zoning was greatly flawed. And it failed litmus test in 2005 when the Moment magnitude (Mw) 7.6 earthquake devastated Muzaffarabad, and caused extensive damage and a death of more than 80,000 people. The country was violently shaken by the loss of people and started to rethink over the adaptation of strict building codes, and in 2007 Pakistan Building Code was adapted, which is mostly based on the 1997 Uniform Building Code. However, on ground, as September 24 quake in Mirpur has proven, there is still a long way to go.
Author is Assistant Professor in Structural Geology, Physical & Geological Sciences at the Universiti Brunei Darussalam. He can be reached at: [email protected]