Investigation of seismicity in Hindu Kush and comparison with the seismicity in Iran

Category Tectonic & Seismotectonic
Group GSI.IR
Location The 24 Symposium of Geosciences
Holding Date 26 August 2007

Investigation of seismicity in Hindu Kush and comparison with the seismicity in Iran

 

Nadia Tahernia1 , M. R. Gheitanchi 1, 2

1. Azad University, North Tehran Branch

2. University of Tehran, Geophysics Institute

 

Abstract:

To investigate the seisimicity of Hindu Kush and Iran and comparing them with each other, seisimicity maps for the past 40 years were provided.The a and b values were calculated for Hindu Kush and compared with the a and b values in different parts of Iran. The vertical cross sections across the Hindu Kush main fault and across the main faults of Iran were provided. The graph of accumulated energy released in 5 years intervals from 1964 to 2004 for Hindu Kush and active zones in Iran were calculated. Seismic energy released in Hindu Kush is higher than in Iran. As expected, the rate of seismic energy in Zagros is larger than other parts of Iran. the time- frequency and magnitude- frequency diagrams for both regions were provided. Distributions of epicenters indicate high seismic activities in both Hindu Kush and Iran, although the number of events in Hindu Kush is relatively higher than in Iran. In Hindu Kush, the majority of the large earthquakes have depth range from 100 to 300 kilometers. Epicenters of small earthquakes are scattered, having depth less than 100 kilometer. In different parts of Iran, earthquakes have shallow depths. From seisimicity point of view, Zagros is more similar to Hindu Kush because of having many moderate and small earthquakes, as well as regular pattern of seismic activity. From tectonic point of view, Makran is similar to the Hindu Kush and both follow a kind of subduction zone pattern of seismic activity.

tags: QAZVIN