The Stresses of Kashmir Valley

Kashmir Valley is a place of intense natural beauty, but beneath that beauty lies impending dangers for the inhabitants of Kashmir. Each year the Indian subcontinent continues to push northward into the Eurasian plate. Overtime, the movement of the Indian plate has led to the development of the Himalayas (Hough, 2009). The subduction of the Indian plate has also led to increasing earthquake magnitudes in the region. In 2005, the Muzaffarabad Earthquake occurred, killing over 80,000 people. According to the research of Hough her and colleagues, the 7.

6 magnitude of the Muzaffarabad Earthquake is just the beginning (Hough, 2009). Due to the convergence of faults in the Himalayas, earthquakes with magnitudes of 8.5 or higher are unavoidable (Hough, 2009). In an effort to limit the amount of civilian deaths, it is important for these scientists to study past earthquakes to predict future events in Kashmir and the rest of the Himalayas.

As time progresses and technology continues to develop, scientists gain more and more methods for researching past geologic events such as earthquakes. The primary method that Hough and her team used for predicting future earthquake magnitudes came from past historical records. Written records in the Kashmir Valley date back nearly 5,000 years. However, information regarding earthquakes only reaches to the 16th century (Hough, 2009). Using the records of past inhabitants of the Kashmir Valley, earthquake engineers were able to gain knowledge about the extent and expanse of damage in the region. Hough explains that, at times, the records were difficult to piece together. Certain accounts were repeated with slight variations and others contained innumerable differences in the names of the cities (Hough, 2009). Eventually the scientists were able to put together a map of the region to determine the expanse of the damage. The records were also helpful for following the string of strong aftershocks that took place following the mainshock. By mapping out the damage and aftershocks, the engineers were able to ""tentatively assign a magnitude to the earthquakes in the records. Hough goes on to admit that the assigned rating contained imprecision and that a higher magnitude was possible (Hough, 2009).

Aside from the historical records, Hough and her colleagues were also able to visit the Kashmir Valley to further fit the records into a single, comprehensive map and timeline of events (Hough, 2009). The trip allowed the scientists to view the landscape for themselves to prove or disprove the accounts from within the records. One specific site was that of the Martand Sun Temple. Upon observation, the scientists discovered that the shocks and damage in that region were far less severe. The lack of damage was also in part due to the superior construction techniques and geologic features that the buildings were constructed upon (Hough, 2009). After the trip, Hough and her team confirmed the previously developed magnitude that was given to the earthquake. The last method that was touched upon in the paper was the use of GPS measurements to determine the overall northward movement of the Indian plate (Hough, 2009). The GPS was able to give more precise measurements to add to the research.

Following the research, the team was able to pinpoint a few different results. The most important results were the specifications of the 1555 earthquake. First and foremost, the earthquake was assigned a magnitude of 7.6 (Hough, 2009). Using the historical records, the scientists were also able to piece together the expanse of the 1555 earthquake in relation to neighboring cities (see Figure 1). Using GPS, Hough and her colleagues determined that the Indian plate is moving northward at a rate of 15 millimeters per year. Finally, the team discovered that the 2005 Muzaffarabad Earthquake intensified the stresses that were previously occurring because of the 1555 earthquake (Hough, 2009).

Interpretations led to a slew of results from the research. The most substantial result is that a danger for mega-earthquakes exists across all of the Himalayas. Earthquakes will continue occurring as long at the Indian plate continues subducting beneath the Eurasian plate (Hough, 2009). The 1555 earthquake proves that large earthquakes occurred in the past, and the 2005 earthquake proves that strong earthquakes are continuing now. According to the scientists, there are still many unknowns when it comes to earthquakes. Future earthquakes may occur beyond the Kashmir Valley, but it is hard to know for sure, as earthquakes do not follow an exact pattern each time. Hough and her team also decided to compare the Kashmir Valley and Himalayas to other major faults. Other faults have histories of multiple successive earthquakes as stress is released, an idea that can also be linked to the Himalayas. The 2005 Muzaffarabad Earthquake may only be the first in a line of strong earthquakes along the fault (Hough, 2009).

Overall, when it comes to my limited knowledge of earthquakes, I agree with the interpretations of Hough and her team. The history of large earthquakes that was determined through the historical records definitely point toward strong earthquakes in the future. As the Indian plate subducts, it will create deeper and stronger releases of tension and stress. It was very intelligent of the team to look toward other major faults to determine what is happening in those locations. Not all faults will act exactly the same, but there may be some trends that can also be applied to the fault between the Indian subcontinent and the Eurasian plate. I also really enjoyed that Hough explained some of the challenges that she and her colleagues faced. It became apparent that the historical records were difficult to work with at times, especially when it came to the names of the cities. It was from these challenges that I came to the conclusion that more research should be conducted. While I am aware that the non-technical historical records can be very useful in understanding past earthquakes, I also believe that further research would be helpful to support the ideas put in place. It is my hope that future paleoseismological investigations along the Himalayan arc will be able to support the ideas of Hough and her team.

References

1. Hough, S., Bilham, R., & Bhat, I. (2009). Kashmir Valley Megaearthquakes. American Scientist, 97(1), 42-49. doi:10.1511/2009.76.42

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