GEODETIC-BASED AND GEOLOGICAL-BASED EARTHQUAKE RATES

سال انتشار: 1398
نوع سند: مقاله کنفرانسی
زبان: انگلیسی
مشاهده: 690

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شناسه ملی سند علمی:

SEE08_012

تاریخ نمایه سازی: 27 خرداد 1399

چکیده مقاله:

The Iranian plateau is a seismically active region in the world (Berberian and Yeats 1999). In different seismic zones,including Zagros, Alborz, Azerbaijan, Kopet Dagh, and Central-East Iran, large-magnitude earthquakes are observed. It is shown that recurrence times of large-magnitude earthquakes are more than 2000 years (Berberian and Yeats 2001) in the Iranian Plateau and further investigations that had been carried out after Tabas 1978, Manjil 1990, Bam 2003 and Ahar 2012 dual large-magnitude earthquakes confirmed long quiescence period between such earthquakes. Given that large-magnitude earthquake recurrences are more than several thousand years, observed seismicity, paleoseismological investigations are either short or incomplete. Merely using one dataset cannot constrain earthquake statistics to the degree necessary for a precise hazard assessment. In other words, the seismic hazard assessment using historical and instrumental can lead to underestimated results. In recent decades, GPS networks are developed all over the world, and several studies are carried out on geodetic observations, and strain rates over large areas are depicted with different degrees of precision. For various regions (e.g., California (Field et al. 2015), Canada (Mazzotti et al. 2011), Japan, New Zealand (Stirling et al. 2002) and Italy (Slejko et al. 2010), strain rates, which are derived from geodetic and geological data, are converted to seismic moment rates and earthquake statistics. In this contribution, we aim to estimate earthquake rates based on a combination of observed seismicity and geodetic strain rates for the Iranian Plateau. Using long-term deformation rates of the Iranian Plateau that are estimated by geodetic and geological data (Khodaverdian et al. 2015), deformation-based earthquake rates are obtained. The results show that catalog-based rates are really different from deformation-based rates. These outcomes will provide the possibility of a comparison between traditional seismic-based and novel deformation-based hazard analysis and more accurate seismic hazard assessment.

نویسندگان

Alireza Lotfi

Ph.D. Student, International Institute of Earthquake Engineering and Seismology, Tehran, Iran

Hamid Zafarani

Associate Professor, International Institute of Earthquake Engineering and Seismology, Tehran, Iran

Alireza Khodaverdian

Postdoctoral Researcher, Swiss Seismological Service, ETH Zurich, Sonneggstrasse ۵, ۸۰۹۲ Zurich, Switzerland