فهرست مطالب

مجله علوم و مهندسی زلزله
سال ششم شماره 3 (پیاپی 20، پاییز 1398)

  • تاریخ انتشار: 1398/11/08
  • تعداد عناوین: 10
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  • احمد رشیدی*، نیره صبور صفحات 1-16

    با استفاده از پارامترهای قطعه بندی، درازای گسیختگی (در طی هر زمین لرزه)، میزان جابه جایی بر روی گسل ها و الگوی تکرار رویداد زمین لرزه ها؛ رسیدگی ساختاری گسل های باختر و جنوب بلوک لوت مورد ارزیابی قرار گرفتند. در این مطالعه طیف پاسخ جنبش زمین لرزه های بزرگ روی داده در منطقه، تحلیل شدند. بر اساس نتایج حاصله، گسل کوهبنان: نارس؛ بم: میانه تا نارس؛ گوک، لاله زار، کهورک: رسیده می باشند. در بحث تحلیل فرکتالی و رشد و بلوغ پهنه های گسلی منطقه، از روش مربع شمار استفاده شد. بر اساس محاسبات انجام شده، بعد فرکتالی گسل های کوهبنان و شاخه های جنوبی آن، گسل های بم، کهورک، فاریاب، چاه مزرعه (اسفندقه) و گوک نسبت به بقیه گسل ها کمتر است. در امتداد این گسل ها، رومرکز زمین لرزه ها تمرکز بیشتری دارند. بعد فرکتالی با نزدیک شدن به حاشیه داخلی بلوک لوت افزایش پیدا می کند. این افزایش نشان از بالا بودن پراکندگی میدان تنش در این منطقه است. بعد فرکتالی سامانه گسلی نایبند (721/1-56/1) و گسل سبزواران باختری (68/1-52/1) از شمال به جنوب کاهش و گسل گوک (68/1-52/1) از شمال به جنوب افزایش پیدا می کند. بر این اساس قطعات جنوبی سامانه گسل نایبند و سبزواران باختری و قطعات شمالی سامانه گسلی گوک نارس تر می باشند و توان ایجاد خطر لرزه ای جدی تری را دارند. بر اساس نتایج حاصله از مبحث رسیدگی ساختاری و بررسی ابعاد فرکتالی، لرزه خیزترین گسل های منطقه گسل های کوهبنان، بم، کهورک، گوک، لاله زار، فاریاب و چاه مزرعه (اسفندقه) می باشند.

    کلیدواژگان: رسیدگی ساختاری، رفتار لرزه ای، گسیختگی سطحی، تحلیل فرکتالی، لرزه زمین ساخت، طیف پاسخ، بلوک لوت، ایران
  • یاسمن ملکی یورتچی*، مصطفی علامه زاده صفحات 17-25

    یکی از مهم ترین ویژگی ها در سری های زمانی زمین لرزه، تعیین میزان همبستگی هایی است که بین زمین لرزه ها در یک منطقه خاص وجود دارد. این مقاله به برآورد همبستگی ها در سری های زمانی مستخرج از داده های زمین لرزه کالیفرنیا، که طی سال های 2002 تا 2016 رخ داده اند، می پردازد. داده ها از 1 جمع آوری شده اند. میزان همبستگی ها یا حافظه دور برد سری زمانی، توسط پارامتر هرست وابسته به زمان، ، و به صورت موضعی، اندازه گیری می شود. پارامتر هرست را به کمک  الگوریتم میانگین متحرک روند زدا یا به اختصار ، برآورد می کنیم. دلیل استفاده از این روش برآورد، توجه به ساختار مقیاس پایایی زمین لرزه ها و همچنین نوسانات پارامتر هرست نسبت به زمان است. جهت ارزیابی دقت این روش، ابتدا پارامتر هرست را در داده های شبیه سازی شده برآورد می کنیم و میانگین مربعات خطا  را، به عنوان ملاکی از دقت روش، به دست می آوریم. سپس  را جهت تعیین میزان تغییرات و همبستگی بین زمین لرزه های متوالی، در داده های زمین لرزه کالیفرنیا، محاسبه می کنیم. در مواجهه با داده های زمین لرزه، مشاهده می کنیم که پارامتر هرست، دارای تغییرات قابل توجهی نسبت به زمان است درصورتی که در داده های شبیه سازی شده، این میزان تغییرات دیده نمی شود. از مزایای روش ، این است که در این روش به هیچ گونه فرض توزیعی از متغیرهای تصادفی، نیاز نداریم. به علاوه، این روش، برتری قابل توجهی نسبت به روش های موجک و طیف توان با مرتبه بالا دارد که بر اساس تبدیل لژاندر یا فوریه از گشتاورهای مرتبه  محاسبه می شوند. با به کارگیری این روش برآورد در داده های زمین لرزه کالیفرنیا، ملاحظه می شود که مقدار  بین 4/0 و 6/0 نوسان می کند. در مواردی که مقدار پارامتر از 5/0 بیشتر است، نشان دهنده ی وجود همبستگی دوربرد به مقدار کم است و مقادیر پارامتر هرست کمتر از 5/0 بیانگر عدم همبستگی بین مشاهدات متوالی است.

    کلیدواژگان: برآورد پارامتر هرست وابسته به زمان، روش میانگین متحرک روند زدا، داده های زمین لرزه کالیفرنیا
  • محمدرضا آرم*، بابک خزاعی مقدم صفحات 27-42

    در این پژوهش سعی شده است که پارامترهای لرزه ای برای منطقه قم محاسبه گردد. برای نیل به این هدف از روش حل معکوس تعمیم یافته استفاده شده است که در ابتدا توسط اندروز [1] ارائه شد. برای استفاده از این روش ابتدا بانک داده های شتاب نگاری ایجاد و داده های شتاب نگاری همگی از شبکه شتاب نگاری سازمان تحقیقات راه، مسکن و شهرسازی استخراج شد. برای تهیه بانک داده ها، تمامی رکوردهای شتاب مربوط به منطقه مورد مطالعه از بقیه رکوردها جدا شد و سپس مولفه های قائم و افقی هر رکورد استخراج گردید. پس از تهیه بانک داده ها، تمامی رکوردها تصحیح شد و موج برشی مستقیم از کل رکورد جداسازی گردید. طیف فوریه برای رکوردهای به دست آمده محاسبه شد و در 20 فرکانس بین 4/0 تا 15 هرتز با فواصل لگاریتمی مساوی از طیف فوریه نمونه برداری به عمل آمد تا داده‏ها جهت استفاده در الگوریتم حل معکوس تعمیم یافته آماده شوند. با استفاده از روش حل معکوس تعمیم یافته و با استفاده از روش اندرو برای مقید کردن درجه آزادی معادله، ماتریس معلومات و مجهولات مسئله تهیه شد. معادله ماتریسی با کمک روش جداسازی مقادیر تکین حل شد. در محاسبه فاکتور کیفیت امواج برشی مدل گسترش هندسی از مدل معتضدیان [2] استفاده شده است. اثرات چشمه، مسیر حرکت امواج برشی و تاثیرات ساختگاهی که ایستگاه ثبت کننده در آن واقع شده است هرکدام به طور مجزا محاسبه شده اند. در این منطقه پارامتر کیفیت امواج برشی برابر محاسبه شده است. مدل استفاده شده برای تحلیل اثر چشمه مدل می باشد و برای محاسبه افت تنش، فرکانس گوشه، بزرگای گشتاوری و غیره از روش جستجوی نقطه به نقطه استفاده شده است و این پارامترها برای تمامی زلزله های بانک داده ها محاسبه گردیده اند. تشدید ساختگاهی نیز برای تمامی ایستگاه های ثبت کننده محاسبه شده است.

    کلیدواژگان: حل معکوس تعمیم یافته، پارامترهای جنبش نیرومند زمین، فاکتور کیفیت، افت تنش، اثر ساختگاهی، استان قم
  • جعفر کارشی، مقداد سمائی*، عبدالحسین فلاحی صفحات 43-70

    نتایج حرکت های زمین به دست آمده از روش های شبیه سازی به شدت بستگی به میزان دقت پارامترهای ورودی دارد، به طوری که می توانند مقادیر بیشینه، محتوای فرکانسی و مدت تداوم حرکت را تحت تاثیر قرار دهند. در این مطالعه به منظور ارزیابی میزان اثرات عدم قطعیت در پارامترهای چشمه، مسیر و ساختگاه، مقایسه ای بین نتایج شبیه سازی 19 سناریوی آزمایشی با پارامترهای متفاوت نسبت به سناریوی مرجع، انجام گرفته است. برای دستیابی به این هدف گسل نیاوران در شمال تهران به عنوان گسل هدف انتخاب شد که با بزرگی گشتاوری 7 به ترتیب باعث ایجاد میانگین شتاب و سرعت حداکثر 600 سانتی متر بر مجذور ثانیه و 60 سانتی متر بر ثانیه در محدوده ی مورد مطالعه می شود. بر اساس نتایج، پارامترهای بزرگی گشتاوری، افت تنش، بخش مربوط به فرکانس فاکتور کیفیت، توزیع هندسی و کاپا بیشترین اثر و پارامترهای شیب گسل، نقطه ی شروع گسیختگی، سرعت گسیختگی، سطح تپنده دارای کمترین اثر بر نتایج هستند. همچنین محدوده ی پایین فرکانسی (کمتر از 1 هرتز) توسط پارامترهای نقطه ی شروع گسیختگی و بزرگی گشتاوری و حرکت های با فرکانس های بالاتر توسط پارامترهای افت تنش، فاکتور کیفیت، کاپا و بزرگی گشتاوری کنترل می شوند.

    کلیدواژگان: شبیه سازی حرکت زمین، سناریوی زلزله، عدم قطعیت پارامترها، EXSIM، گسل نیاوران
  • محمد داودی، مهدی سلیمانی*، محمدکاظم جعفری صفحات 71-84

    در بیشتر مطالعات مربوط به اندرکنش گسلش- خاک- فونداسیون- سازه، تنها فونداسیون مدل شده و اثر سازه با روش هایی مانند سختی معادل یا اضافه نمودن سربار معادل آن در مدلسازی ها دیده شده و از مدلسازی مستقیم سازه در مدل های آزمایشگاهی و عددی خودداری شده است. لذا به نظر می رسد مدلسازی مستقیم سازه بتواند درک بهتری از تاثیر حضور سازه- فونداسیون بر نحوه انتشار گسلش سطحی1 و همچنین بر نحوه عملکرد اعضاء مختلف سازه در حین گسلش را امکان پذیر سازد. در این تحقیق مدلسازی عددی دوبعدی سازه- فونداسیون- آبرفت با اعمال گسلش سطحی معکوس به صورت شبه استاتیکی، در حالت قابهای دو دهانه دارای پی نواری با تعداد طبقات 3 و 7، با استفاده از روش اجزاء محدود و نرم افزار آباکوس انجام شده و تاثیر عواملی نظیر موقعیت قرارگیری سازه، تعداد طبقات و ضخامت فونداسیون در این پدیده اندرکنشی به صورت پارامتریک مورد مطالعه و بررسی قرارگرفته است. بر این اساس بحرانی ترین موقعیت قرارگیری، برای حالتی است که سازه برروی فرادیواره و در فاصله 15 تا 25 متری از محل رخنمون گسلش میدان آزاد2 قرار می گیرد. تاثیر افزایش تعداد طبقات (افزایش سربار) از نظر تغییرشکل های ایجادشده در سازه در مواجهه با پدیده گسلش در حالت های مختلف قرارگیری سازه متفاوت می باشد، اما از نظر تغییرات نیروهای داخلی اعضا سازه ای، افزایش تعداد طبقات باعث ایجاد مقادیر نیروی برشی و لنگر خمشی بزرگتری در طول تیر طبقات و فونداسیون سازه ها در اثر اعمال گسلش می شود. افزایش ضخامت فونداسیون نیز باعث کاهش مقادیر نیروی برشی و لنگر خمشی ایجاد شده در اعضای سازه ای نظیرتیرها در اثر اعمال گسلش می گردد، در نتیجه می تواند به عنوان یک راهکار مناسب در جهت عملکرد بهتر سازه در مواجهه با پدیده اندرکنشی سیستم کوپل، مورد توجه قرارگیرد.

    کلیدواژگان: گسلش معکوس، اندرکنش گسلش-خاک-سازه، اجزای محدود
  • مجید فرین، مسعود حاجی علیلوی بناب*، توحید اخلاقی صفحات 85-101

    در این مقاله شبیه سازی عددی و تحلیل تونل خط 2 مترو تبریز، واقع در ناحیه با فعالیت لرزه ای بالا، تحت تحریکات زلزله های مختلف بررسی شده است. تحلیل های دینامیکی تاریخچه زمانی سیستم به هم بسته خاک-تونل با استفاده از نرم افزار FLAC2D انجام شده اند. رفتار غیرخطی خاک و اندرکنش خاک و سازه با در نظر گرفتن مشخصات مربوط به تونل زیرزمینی مدل شده است. عملکرد لرزه ای مدل به وسیله مدل رفتاری UBCHYST برای خاک ارزیابی گردیده است. این مدل رفتار سیکلی غیرخطی شامل کاهش مدول برشی با کرنش برشی و نسبت میرایی وابسته به کرنش می باشد. پارامترهای مدل UBCHYST به وسیله مقایسه منحنی های کاهش مدول و میرایی حاصل از شبیه سازی مدل با منحنی های دارندلی کالیبره شده و سپس مدل تحت زلزله هایی با ماکزیمم شتاب زمین و فرکانس های غالب مختلف قرار گرفت. نتایج تحلیل های دینامیکی برحسب جابه جایی، تنش موثر و نیروهای داخلی در طی زلزله ارائه شده است. بر اساس تحلیل ها، افزایش ماکزیمم شتاب زمین و ماکزیمم جابه جایی افقی منجر به افزایش نیروهای داخلی دینامیکی در پوشش تونل، افزایش نشست دائمی خاک و کاهش تنش موثر در خاک می شود. به علاوه، پس از هر زلزله مقادیر باقیمانده قابل توجهی برای لنگر خمشی دینامیکی در پوشش تونل در اثر کرنش های تجمعی مشاهده شد درصورتی که مقادیر باقیمانده پس از زلزله برای نیروهای محوری در پوشش تونل کوچک تر است.

    کلیدواژگان: پاسخ لرزه ای، تونل، مترو تبریز، تحلیل عددی، دینامیکی
  • عبدالحمید غفوری، سالار منیعی صفحات 103-123

    این مقاله به ارزیابی رفتار لرزه ای سازه های فولادی مجهز به میراگرهای تسلیمی TADAS با تاکید بر پاسخ پسماند جهت بهسازی لرزه ای قاب های خمشی فولادی اجراشده می پردازد. برای این منظور، پاسخ سه قاب خمشی فولادی با شکل پذیری ویژه و با تعداد طبقات 3، 9 و 20 با و بدون میراگر تحت اثر 11 شتاب نگاشت مقیاس شده دور از گسل به روش تحلیل غیرخطی تاریخچه زمانی با در نظر گرفتن آثار زوال سختی و مقاومت و با تاکید بر پاسخ پسماند مورد ارزیابی قرار گرفته است. با توجه به نتایج به دست آمده، جابجایی های نسبی بین طبقه ای پسماند به طور میانگین در سازه کوتاه مرتبه بین 75 تا 80 درصد، در سازه میان مرتبه 15 تا 85 درصد و در سازه بلند مرتبه 30 تا 80 درصد در طبقات مختلف کاهش نشان می دهد. به علاوه، جابجایی حداکثر در سازه 3 طبقه به طور میانگین حدود 50 درصد و در سازه های 9 و 20 طبقه حدود 10 تا 40 درصد کاهش نشان می دهد. نسبت میانگین جابجایی پسماند به جابجایی حداکثر نیز در هر سه سازه به ترتیب بین 50 تا 65 درصد، 50 تا 55 درصد و 20 تا 50 درصد کاهش داشته است. با افزایش تعداد طبقات، میراگرها تاثیر کمتری در کاهش پاسخ ها و بهبود عملکرد سازه ها نشان می دهند. نتایج نشان می دهد که تعبیه میراگر منجر به کاهش آثار مدهای بالاتر در سازه های بلند و یکنواختی بیشتر در توزیع تقاضاهای تغییر شکل غیرخطی در ارتفاع می شوند. نتایج تحلیل ها و مقایسه پاسخ ها با حدود عملکردی مبتنی بر جابجایی پسماند در نشریه FEMA P-58، نشان می دهد که سازه های مجهز به میراگرهای TADAS، تاب آوری لرزه ای بیشتری نسبت به قاب های بدون میراگر دارند.

    کلیدواژگان: پاسخ پسماند، لرزه ای، میراگرهای فلزی TADAS، تاب آوری لرزه ای، ارزیابی عملکرد لرزه ای
  • ابراهیم فدایی، حمزه شکیب*، علیرضا آذربخت صفحات 125-142

    در طراحی و ارزیابی سازه ها بر اساس عملکرد، شناسایی سطوح عملکرد سازه در سطوح خطر لرزه ای مشخص از اهمیت ویژه ای برخوردار است. در ارزیابی عملکرد لرزه ای سازه های فولادی با سیستم باربر جانبی دوگانه متشکل از قاب خمشی و مهاربندهای همگرا با تحلیل دینامیکی فزاینده، معیارهای مقبول و پذیرفته شده ای جهت تعیین سطوح عملکرد وجود ندارد. در این مقاله معیارهای مناسب و ساده ای جهت تعیین سطوح عملکرد سازه های فولادی با این سیستم سازه ای پیشنهاد گردیده است. بدین منظور متوسط مقادیر شاخص خسارت یک سازه ی مرجع با سیستم قاب خمشی در سطوح عملکرد تعیین شده با استفاده از روش راهنمای FEMA 350 محاسبه و بر مبنای این مقادیر سطوح عملکرد 22 سازه فولادی با سیستم دوگانه با حالات مختلف نامنظمی غیر هندسی در امتداد ارتفاع با تحلیل دینامیکی فزاینده تعیین شده است. بر اساس میانگین ظرفیت تغییر مکان نسبی بین طبقه ای در سطوح عملکرد، معیارهای مناسب و ساده ای جهت تعیین سطوح عملکرد سیستم سازه ای مذکور معرفی گردیده که بر اساس آن مقدار دریفت 9/0 درصد برای شناسایی سطح عملکرد قابلیت بهره برداری بی وقفه و دریفت 5/7 درصد یا کاهش شیب منحنی IDA به 20 درصد مقدار آن در حالت الاستیک برای تعیین سطح عملکرد آستانه فروریزش پیشنهاد شده است.

    کلیدواژگان: سطوح عملکرد، سیستم دوگانه قاب خمشی و مهاربندهای همگرا، شاخص خسارت
  • نغمه پاکدل لاهیجی*، محسن غفوری آشتیانی صفحات 143-155

    ترکیب لرزه خیزی بالا و آسیب پذیری بالای سازه ها در ایران سبب گشته است که ریسک یا خطرپذیری در ایران در سطح بالایی قرار گیرد. به صورت کلی دو رویکرد اصلی در مدیریت ریسک وجود دارند که عبارتند از توزیع ریسک و کاهش ریسک که تمرکز اصلی این تحقیق بر توزیع ریسک است. جهت برآورد منابع مالی موجود جهت مقابله با خسارات زلزله، ابزارهای توزیع ریسک ،که در اینجا سیستم های بیمه زلزله می باشند، با در نظر گفتن آسیب پذیری اقتصادی موجود مالکین و ریسک منطقه، طراحی شده اند. از سوی دیگر، در هر سیستم بیمه زلزله طراحی شده، قابلیت پرداخت حق بیمه ها از سوی ساکنین در جامعه نیز که در پذیرفته شدن سیستم و پایداری آن ضروری است مورد بررسی قرار گرفته است. رویکرد احتمالاتی مدل سازی ریسک مورد استفاده در اینجا، تفاوت زیادی را بین حق بیمه های موجود در کشور و حق بیمه های بر پایه ریسک محاسبه شده نشان می دهد که نشان دهنده اهمیت فراوان در نظر گرفتن واقعی ریسک زلزله در فرآیندهای تصمیم گیری های مالی قبل و پس از وقوع زلزله است. همچنین نیاز به روش های کاهش ریسک برای ساختمان های بسیار آسیب پذیر و لزوم بهره گیری از پوشش بیمه اتکایی و کمک های دولتی برای مدیریت ریسک رویدادهای فاجعه آمیز نشان داده شده است.

    کلیدواژگان: آسیب پذیری سازه ها، توزیع ریسک زلزله، بیمه زلزله بر پایه ریسک و قابلیت پرداخت حق بیمه زلزله
  • عادل فرجی، حمید زعفرانی*، فرخ پارسی زاده صفحات 157-169

    این پژوهش به منظور بررسی و ارزیابی میزان آگاهی مردم شهر بابل از لرزه خیزی منطقه و آمادگی آنان برای مقابله با این وضعیت صورت گرفته است. بدین منظور و برای دستیابی به میزان آگاهی مردم از زلزله خیز بودن منطقه، نیازهای ضروری آنان، رفتارهای آنان هنگام وقوع زلزله، آمادگی در برابر آن و متداول ترین روش آموزشی دریافت و انتقال مفاهیم مربوط به زلزله و موارد مشابه پرسش نامه ای در میان مردم شهر توزیع شد. تعداد 426 پرسش نامه به روش تصادفی ساده و با سوال از افراد بالای هجده سال در میدان ها، چهارراه ها، دانشگاه ها، اداره ها و بیمارستان های شهر (در وقت ملاقات) تکمیل گردید. سپس، پاسخ های دریافتی با استفاده از نرم افزار تحلیل آماری اس پی اس اس مورد تجزیه وتحلیل قرار گرفت. بر اساس نتایج به دست آمده، 62 درصد پرسش شوندگان، مطالب آموزشی پیرامون زلزله دریافت کرده اند ولی 70 درصد از آنها و همچنین 81 درصد از پرسش شوندگان گروه سنی 18-25 سال، بابل را شهری زلزله خیز نمی دانند و یا اطلاعی از زلزله خیز بودن آن ندارند. یکی از دلایل چنین دیدگاهی در نظر مردم بابل در تصور غلط آنان از معنای زلزله خیزی ریشه دارد. آنها منظور خود از زلزله خیز بودن شهر را، در چندین بار تجربه کردن زلزله در سال و یا رخداد زلزله در این شهر بیان می کردند. در نتیجه، آموزش مطالب مربوط به زلزله به همراه آگاهی بخشی نسبت به وضعیت لرزه خیزی شهر باید به منزله اولویت در نظر گرفته شود.

    کلیدواژگان: زلزله، آگاهی، آمادگی، بابل
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  • Ahmad Rashidi *, Nayereh Sabour Pages 1-16

    The study area is located in the W-S Lut block. Eleven destructive earthquakes, from 1977 to 2012, were accompanied by about 185 km of the surface rupture in the South and Southwest of the Lut block. These earthquakes have resulted in ~44,700 human fatalities, ~36,646 injured and more than 100,000 homeless. In the western and southern margins of the Lut Block, there is a complete absence of historical records of earthquakes up until ~160 years ago. This lack of records may be resulted from the isolation of the area due to proximity to deserts (Ambraseys and Melville, 2005; Berberian, 2005). Nevertheless, some historical earthquakes for the pre-1900 period are reported (e.g. Berberian, 1977; Ambraseys et al., 1979; Berberian et al., 1979; Ambraseys and Melville, 2005). There is no reliable estimation of the seismotectonic characteristic in this region; therefore, the seismic hazard assessment is not accurate enough. It is important that the seismicity of the area and its temporal and spatial variations are viewed as snapshots of the ongoing tectonic activities. Therefore, identification of the structural maturity and fractal dimension may provide complementary deductions for more realistic analysis and interpretation of the observations. We investigated a number of faults in this area that have high potential for generating destructive earthquakes. The faulting patterns appear to preserve different stages of fault development. We investigated the distribution of active faults and the role that they play in accommodating tectonic strain in the SW-Lut. For interpretation of structural maturity, we used fault segmentation, rupture length, displacement on the fault surface and pattern of repetition of the earthquake event. Based on the results of this study, the Kuhbanan fault is immature, the bam fault is middle until immature and Gowk, Lalehzar, and Kahourak are mature. For the fractal analysis and the maturity of the fault zones in the area, we used fractal dimension. Based on the calculations, the fractal dimension of the Kuhbanan fault and its southern branches, Bam, Kahourak, Faryab, Chahmazrae (Esfandaqeh) and Gowk faults are less than the other faults in the study area. Along these faults, the focal mechanism of the earthquakes are more focused. Inner edge of the Lut block, the fractal dimension are increasing. This increase show high distribution of stress in this area. The dispersion of the stress field decreased the amount of stress and seismic activity in this area. The fractal dimension of the Nayband fault system (1.56-1.72) and West Sabzevaran fault (1.52-1.68) reduce from north to south and Gowk fault (5.15-1.68) increase from north to south. Therefore, the southern part of the Nayband and West Sabzevaran faults and the northern parts of the Gowk fault are immature. These area have serious risk for the area. Based on the results of structural maturity and fractal dimensions, Kuhbanan, Bam, Kahourak, Gowk, Lalehzar, Faryab and Chahmazrae (Esfandaqeh) faults will create high risk of seismicity.

    Keywords: Structural Maturity, Seismic Behavior, Surface Rupture, Fractal Analysis, Seismotectonics, Response Spectrum, Lut Block, Iran
  • Yasaman Maleki *, Mostafa AllamehZadeh Pages 17-25

    In this paper, the dynamics of the seismic activity and fractal structures in magnitude time series of Sarpol-e Zahab earthquakes are investigated. In this case, the dynamics of the seismic activity is analyzed through the evolution of the scaling parameter so-called Hurst exponent. By estimating the Hurst parameter, we can investigate how the consecutive earthquakes are related. It has been observed that more than one scaling exponent is needed to account for the scaling properties of earthquake time series. Therefore, the influence of different time-scales on the dynamics of earthquakes is measured by decomposing the seismic time series into simple oscillations associated with distinct time-scales. To this end, the Empirical Mode Decomposition (EMD) method was used to estimate the locally long-term persistence signature derived from the Hurst exponent. As a result, the time dependent Hurst exponent, H(t), was estimated and all values of H>0.5 was obtained, indicating that a long-term memory exists in earthquake time series. The main contribution of this paper is estimating H(t) locally for different time-scales and investigating the long-memory behavior that exists in the non-stationary multifractal time-series. The time-dependent scaling properties of earthquake time series are associated with the relative weights of the amplitudes at characteristic frequencies. The superiority of the method is the simplicity and the accuracy in estimating the Hurst exponent of earthquakes in each time, without any assumption on the probability distribution of the time series. We investigated the negative and positive autocorrelations that exist between consecutive seismic activities by estimating the time-dependent Hurst parameter, H * (t). To this end, the empirical mode decomposition and the Hilbert-Huang transform are applied. Using this method, the seismic activities are studied locally, and the autocorrelation between consecutive earthquakes are estimated in each time. We have investigated the superiority of the estimator by simulation. Furthermore, the method is applied in estimating H * (t) of earthquakes occurred in Sarpol-e Zahab during November 12, 2017 to January 20, 2018. By estimating the Hurst parameter locally, and considering the values of H * (t) that are greater than 0.5, we identify that the long memory behavior exist in consecutive earthquakes during 25/11/2017 and 13/1/2018. It is also seen that, in spite of small values of H * (t) for some times, which shows the stochastic behavior in earthquakes, the local Hurst parameters are tending to be greater than 0.5, and after this patterns, a peak in magnitude is seen. This paper shows that the combination of the EMD and its associated Hilbert spectral analysis offers a powerful tool to uncover the time-dependent scaling patterns of consecutive seismic activities data. In this paper, we investigate the long-range correlations and trends between consecutive earthquakes by means of the scaling parameter so-called locally Hurst parameter, H(t), and examine its variations in time, to find a specific pattern that exists between foreshocks, main shock and the aftershocks. The long-range correlations are usually detected by calculating a constant Hurst parameter. However, the multi-fractal structure of earthquakes caused that more than one scaling exponent is needed to account for the scaling properties of such processes. Thus, in this paper, we consider the time-dependent Hurst exponent, to realize scale variations in trend and correlations between consecutive seismic activities, for all times. We apply the Hilbert-Huang transform to estimate H(t) for the time series extracted from seismic activities occurred in Iran. The superiority of the method is discovering some specific hidden patterns that exist between consecutive earthquakes by studying the trend and variations of H(t). Estimating H(t) only as a measure of dependency may lead to misleading results, but using this method, the trend and variations of the parameter is studying to discover hidden dependencies between consecutive earthquakes. Recognizing such dependency patterns can help us in prediction of mainshocks.

    Keywords: Hilbert Spectral Analysis, Hurst Parameter, Time-Dependent Scaling, Estimating
  • Mohammad Reza Aram *, Babak Khazaie Moghaddam Pages 27-42

    Being located on the seismic belt, Iran has experienced frequent and sometimes intense seismic activities. Many researchers discussed about seismotectonic characteristics of Iran, and based on similarities in seismotectonic parameters, they divided Iran into different tectonic provinces. Most acceptable seismotectonic divisions for Iran is provided by Mirzaie which introduces five tectonic provinces; Alborz-Azerbaijan (North and Northwest of Iran), Kopet Dagh (Northeast of Iran), Zagros (Southwest of Iran), Makran (Southeast of Iran) and Central-East of Iran. In this study, Qom region located in Central-East province is discussed, which is a seismic active region and faced large earthquakes such as Avaj (22/6/2002) with magnitude 6.1 epicentered in 35.71˚N and 49.02˚E, Silakhor(30/3/2006) with magnitude 6.2 epicentered in 33.69˚N and 48.95˚E and Kahak (18/6/2007) with magnitude 5.7 epicentered in 34.54˚N and 50.94˚E, hence it is very important to have estimates of earthquake parameters such as anelastic and geometrical attenuation, average stress parameter, and site amplification for this region, which has high seismicity rates and especially has populated areas with high seismic risk. In this study, generalized inversion method is used which is common approach for deriving the modeling parameters from the empirically observed data. Generalized inversion method introduced by Andrews. Andrews recast the spectral ratios approach into an inverse problem for earthquakes and stations with multiple records. This method has been later improved by other researchers. Ground-motion amplitudes are affected by source, path and site effects. Source term includes the effect of magnitude, stress parameter and the type of faulting on the observed ground-motion amplitude. Path term includes both anelastic and geometrical attenuation. Site term includes the effect of the near surface features like geology and topography on the observe data that consists of site amplification and high frequency attenuation. High frequency attenuation is calculated by estimating kappa using Hough-Anderson method. Convolution of these effects is what stations are recording as earthquake records. Generalized inversion method introduces a way to divide recorded spectrum into mentioned effects. At first, by transforming time-domain data into frequency-domain and then with the aid of natural logarithm operator, a linear equation is achieved. Afterward, we can derive modeling parameters for each of the effective terms. In this study, for source term, the Brune source model (omega square) is used. To remove the trade-off between anelastic attenuation and geometrical spreading in path effect, geometrical spreading model from previous studies is used. In this formulation, all the site spectra may be multiplied by an arbitrary function of frequency and all the source spectra divided by the same function without changing the fit to the data that adds a degree of freedom to our system, which in this study is resolved by using predefined site term for reference site (Arak station) as it is located on hard rock (Vs30 >700 m/s) and can be evaluated using Boore-Joyner generic rock site model. Database is constructed from 39 number of strong-motion records, recorded in 14 stations from 9 earthquakes with magnitude greater than 4 within target region. At first, horizontal and vertical components are extracted (horizontal component is considered as geometric mean of two horizontal components) and corrected using wavelet de-noising method. Shear wave extracted from all records using Husid method for beginning of S-wave and Kinoshita method for end of S-wave and Fourier spectrum is sampled in frequencies between 0.4 and 15 Hz. A system of over-determined equations is resulted. Stress drop, corner frequency, moment magnitude and seismic radius is calculated for each earthquake using Grid-search method. The relation between S-wave energy and moment magnitude is expressed by , regional stress drop is 81 bar and frequency dependent quality factor is that aligns well with previous studies in this region. Calculated quality factor indicates that the region of study has high seismicity rates. Also site amplification is calculated for all the stations in the selected frequency range of 0.4-15 Hz. Results of this study can further be used for a better evaluation of seismic hazard in a region of interest.

    Keywords: Generalized Inversion Method, Strong-Motion Parameters, Quality Factor, Stress Parameter, Site Amplification, Qom Province
  • Jafar Karashi, Meghdad Samaei *, Abdolhossein Fallahi Pages 43-70
    Introduction 

    In strong ground motion simulation methods, results are strongly dependent on the accuracy of input parameters; so that the resultant peak parameters, frequency content and the duration of motion could be easily affected. In the current study, for investigating this matter further, the extent in which each parameter influences the results, has been examined. For this purpose, a reference simulation scenario considering Niavaran fault has been assumed first. Then, by increasing and decreasing input parameters, 19 other scenarios have been considered and the results have been explored. 

    Methodology 

    Stochastic finite fault method [1] was used for ground motion simulation. In this method, which has its roots in stochastic point source method [2], the fault plane is divided into sub-faults, each of which acting as a point source. Resultant recordings from each sub-fault are added in the observation point considering their time delays so the main recording is obtained. Stochastic methods benefit from using the Fourier amplitude of motion that includes the effects of source, path and site. Therefore, in this study, by changing each of these parameters and parameters relating to the geometry of the fault, accurate selection of these parameters are illustrated. Niavaran fault with length and width of 44 and 20 km respectively, has the capacity of producing an earthquake with magnitude 7. By changing the dip and rupture starting point as fault geometrical parameters, moment magnitude, rupture velocity, stress drop and pulsing area as source parameters, quality factor and geometrical spreading as path parameters and kappa as site parameter, we investigated the effect of uncertainty of these parameters on the results.

    Results and discussion

    At first, the simulation was done for the reference scenario with magnitude 7 and on engineering bedrock (Vs(30)=620 m/s) for distances up to 60 km from the fault plane. It should be noted that rupture starting point was decided based on the study of Chiou and Youngs [3] and other parameters are chosen based on the study of Motazedian [4]. For the site amplification Boor and Joyner [5] curves were used. For this scenario, at closest point with 3 km distance from the fault plane, PGA reaches 600 cm/c/c and PGV to about 60 cm/s. Most motions are observed in near field points, especially those above the rupture plane in the area of 1300 km2 which an average have acceleration of 330 cm/s/s. The results for PGA and PGV are compared with four ground motion prediction equations and seem to be satisfactory. Considering that the target fault is within the area of Tehran, this scenario can be a real threat to the city. After comparing the testing scenario with the reference one, the effects of uncertainty could be stated as follows: Parameters that have the most significant effects on the motions are the parameters with greater moment magnitude, greater stress drop, greater b coefficient of geometrical spreading and smaller kappa. Therefore these parameters could be called “worst case scenario” since these scenarios besides having larger PGA and PGV, have a bigger area affected with peak parameters. Effects of uncertainty of parameters have also been investigated in frequency domain. Motions with low frequency are usually controlled by rupture starting point and moment magnitude parameters, which have most effects on larger structures. Higher frequencies which are more important for smaller structures are controlled by stress drop and quality factor parameters. The most important effects of tested scenarios compared to the reference one is observed in distances under 30 km, therefore it is necessary for the near field hazard analysis that parameters with highest accuracy are considered.

    Keywords: Strong Motion Simulation, Earthquake Scenario, Parameter Uncertainty, EXSIM, Niavaran Fault
  • Mohammad Davoodi *, Mehdi Soleimani, Mohammad Kazem Jafari Pages 71-84

    In most studies of faulting-soil-foundation-structural interaction, the structural effects is considered by modeling the equivalent hardness or adding equivalent overload to the foundation. Consequently, direct modeling of the structure is avoided in laboratory and numerical models. Based on the above-mentioned remarks, direct modeling of the structure seems to allow a better understanding of the structure-foundation effect on the distribution of surface fault rupture. In the current study, a 2D finite element numerical modeling of structure-foundation-alluvium interaction has been made by applying reverse surface faulting. The structures are modeled as two span frames with 3 and 7 floors with strip foundation. The effects of different factors on the interaction phenomenon including: location of the structure (Table 1), number of floors and foundation thickness have been studied parametrically. The results of the parametric studies indicated that the most critical situation of the structures occurs when it is located on the hanging wall with a 15 to 25 meters far from the free field fault outcrop. Related to the structural location, the effect of increasing floor number on structural deformation is not unique. Nevertheless, this phenomenon increases the internal forces of structural members. In fact during surface fault ruptures, greater amounts of shear forces and bending moments was created along the beam floors and foundation structures by incasing the floor numbers. Furthermore, increasing the foundation thickness reduces the induced shear forces and moments of the structural members. Consequently, it is recommended to use the foundations with a high thickness for improving the structural performance against surface fault ruptures.

    Keywords: Surface Fault Ruptures Reverse Fault, Finite Element, Rupture- Soil-Structure Interaction
  • Majid Farrin, Masoud Hajialilue-Bonab *, Tohid Akhlagi Pages 85-101

    In this paper, the seismic response of Tabriz subway tunnel line 2, located in the high seismic activity area in the northwest of Iran, was studied by using the two-dimensional finite difference program FLAC 7.0. The dynamic time history analyses of the coupled tunnel-soil system were carried out under plane strain conditions. The tunnel lining is made of segments of precast concrete with a thickness of 0.35 m and length of 1.50 m installed behind the shield of the earth pressure balance TBM. In the study area of the path, the type of the soil is mostly GM and SM, and the water level is approximately 10 m under the ground surface. By considering the location of Tabriz subway tunnels that are close to the Tabriz north fault, the characteristics of three near-field earthquakes, Kocaeli, Kobe, and Chi-Chi, were used for the numerical analysis. In this study, the tunnel was meshed by linear elements, whereas the soil was modeled with quadratic plane-strain elements. The linear elastic model was assumed for the tunnel behavior, while the combined hysteretic total-stress constitutive model (UBCHYST) was used to model the soil behavior. This constitutive model simulates nonlinear cyclic behavior containing degradation of shear modulus with shear strain and strain-dependent damping ratio. Modulus degradation and damping curves proposed by Darendeli were used for calibrating the UBCHYST model parameters. Based on the sensitive analysis, the width and height of the model were selected 80 m and 50 m, respectively. The free-field boundary was assigned to the lateral boundaries so that it supplies similar conditions to that of an infinite model. The interaction effects of soil-lining were also taken into account by applying interface elements. In addition, in dynamic analyses, seismic ground motions related to the shear waves were applied to the base of the models as a function of time. Generally, the model analysis was conducted in three phases. First, the soil elements were loaded under a geostatic condition to obtain the natural steady state. These values were used as initial stress for the next calculations. Then, the concrete lining was placed in the soil, the interface properties were applied and thus, the model was analyzed again. In the static analysis, the soil-lining system was under gravity loading only, the base boundary was fixed in all directions and the side boundaries were fixed in the x-direction. Finally, the seismic analysis was carried out. According to the performed analyses, the natural frequencies of the soil layers and the soil-tunnel system were obtained 3.50 and 3.46 Hz, respectively. Therefore, the existence of the tunnel inside the soil decreases the natural frequency of the system. Also, the ratio of calculated acceleration at the different depths to the base acceleration along the tunnel is generally larger than one, which indicates the tendency of the model to amplify the base signal moving toward the ground surface. The Kobe earthquake with two peak ground accelerations (PGA=0.175g and 0.35g) was chosen as the input seismic load applied to the model base for evaluating the impact of the earthquake maximum amplitude. According to the analysis results, by increasing the earthquake maximum amplitude, the ground surface settlement increase as well. In addition, dynamic axial force and bending moment caused in the lining tunnel increase by increasing peak ground acceleration and ground surface displacement during earthquake. It should be noted that a dependence of the increment of bending moment and axial force on the ground surface settlement was observed. Also, at the end of the analysis, the residual axial force remaining in the lining is the same for both earthquakes. In order to study the effects of earthquake frequency content, acceleration time history of three earthquakes (Kocaeli, Kobe, and Chi-Chi) with different predominate period (1.40, 0.16 and 0.93sec, respectively) and the constant PGA (0.35g) were applied to the model. Based on the analysis results, for a given PGA, not only decreasing the predominate frequency of earthquake has the effect on increasing of internal forces, but also other earthquake characteristics such as ground displacement and energy density of earthquake have their own effects. Furthermore, large residual values were observed after each earthquake for dynamic bending moments because of cumulative strains during the earthquake, but smaller residual values were observed after each earthquake for the dynamic axial forces. Moreover, the peak values of the dynamic bending moment are shown near the crown and the shoulders of the tunnel.

    Keywords: Seismic Response, Subway Tunnel, Tabriz City, Numerical Analysis, Dynamic Analysis
  • Abdolhamid Ghafoury, Salar Manie * Pages 103-123

    Recent approaches in seismic design of structures appreciate a lot of the utilization of structural control systems and energy absorbing devices as a means of reduce the damage caused by earthquakes. Due to their efficiency and appropriate seismic response assessment, TADAS metal dampers are a kind of the energy absorbing systems in passive structural control drawn many researchers and structure designers' attention in order to design new structures and improve seismic performance of existing structures. Growing increase of the utilization of this kind of systems in many countries around the world, such as Japan and U.S., beside the compilation of regulations and building codes in relation to these systems demonstrate the tendency of engineering society to benefit from this simple technology. It is very important, in structure studies after earthquakes, to recognize residual displacement and permanent deformations of structures in order to determine their remaining capacity and extent of damage incurred due to the earthquake. This will be a decisive factor in rehabilitation and repair possibility or destruction necessity of structures. The present research studies the residual displacements behavior of steel moment frames equipped with TADAS yielding devices. For this purpose, SAC steel moment frames with 3, 9 and 20 stories have been used, and structural responses including residual displacements, maximum displacement, relative-story displacement and maximum absolute acceleration have been evaluated by dint of SAP2000 features in nonlinear static and dynamic time-history analyses utilizing 11 far-field seismic records, scaled by methods based on 2800 standard rules and ASCE 7-10 instructions. Results show that, on average, the maximum residual inter-story drifts are reduced 75% to 80%, 15% to 85% and 30% to 80% for the 3-, 9- and 20-story models, respectively. In addition, on average, the maximum displacements are reduced approximately 50% for the 3-story model and 10% to 40% for both 9- and 20-story models. The ratio of residual to maximum displacements are reduced 50% to 65%, 50% to 55% and 20% to 50% for the three models, respectively. Results reveal that the effectiveness of TADAS dampers in reducing the responses and enhancing the seismic performance of building frames are reduced with increasing the height of the structure. Incorporating TADAS dampers also results in more uniform distribution of seismic displacement demands through the height of the structure. Results of this study and comparing the responses with performance limit states defined in FEMA P-58 based on the amount of residual deformations demonstrate that structures equipped with TADAS dampers are more seismic resilient than non-equipped structures.

    Keywords: Residual Response, Seismic, TADAS Metal Dampers, Seismic Resisliency, Seismic Performance Assessment
  • Ebrahim Fadaei, Hamzeh Shakib *, Alireza Azarbakht Pages 125-142

    The Performance-Based Earthquake Engineering (PBEE) has emerged three decades ago in order to improve the safety assessment of structures. The computational advances in past decades paved the way for researchers and engineers to be able to use sophisticated algorithms for analysing complicated structures. PBEE aims at assessing and control the performance in different structural elements during and after a target ground motion. The immediate occupancy, life safety and collapse prevention are three common structural limit states that have been used in most of the regulations around the world. However, quantification of these limit states for different structural systems is somehow not very crystal clearly defined. FEMA 273, FEMA 356, and ASCE 41-13 are some pioneers in this subject in which they compare demand and capacity at each element. Excessing demand to the capacity ratio in one element means that the whole structure fails to comply with the regulations, which might somehow be a conservative approach. However, FEMA 350 is one of the few regulations that uses an approach for the structural assessment as a whole. Dual systems usually provide enough strength, stiffness, and ductility, especially for tall buildings in seismic prone regions. The combination of steel moment frame and the concentric bracing system is one of the most convenient dual systems around the world. The bracing system bears the majority of the base shear; however, after significant buckling of braces, the moment frame behaves as a second line of defence. It is worth mentioning that few attempts have been made in order to quantify the limit states in dual systems. The limit state criteria for individual moment resisting or bracing systems might be different in essence if being used for dual systems. Therefore, limit states for these dual systems should specifically being studied. Therefore, this vital issue is the main focus of the current study. In designing and evaluating structures based on performance, identifying the performance levels of the structure at specific seismic hazard levels is of particular importance. In assessing the seismic performance of dual-steel concentrically braced frames consisting of moment-resisting frames and concentrically braced frames with incremental dynamic analysis, there are no accepted and reliable criteria for determining performance levels. The present study proposes suitable and simple criteria for identifying the performance levels of this structural system. For this purpose, the mean value of the Park-Ang damage index is calculated for a given moment-resisting frame system at the performance levels based on the FEMA 350 guideline approach. On the basis of these values, the performance levels of 22 steel buildings with the dual system with different configurations of non-geometrical irregularity along the height are determined by means of incremental dynamic analysis. The mean damage index for the immediate occupancy and collapse prevention are, respectively, equal to 0.21 and 0.9. These damage indices are accounted for a reasonable representation of the structural performance. Finally, a set of appropriate and straightforward criteria for determining the performance levels of the dual-steel concentrically structural system are proposed based on the average of the capacity of the inter-story drift ratio in each performance level. The inter-story drift ratio equal to 0.9 per cent is proposed for the immediate occupancy limit state. In the case of collapse prevention limit state, the inter-story drift ratio equal to 7.5 per cent or the slope reduction of IDA curve to 20 per cent of the initial slope, each reaches earliest, is proposed as the performance limit state.

    Keywords: Performance Levels, Moment Frame, Concentrically Braced Dual System, Damage Index
  • Naghmeh Pakdel-Lahiji* Mohsen Ghafory-Ashtiany Pages 143-155

    Iran is located in a high seismic area and has many vulnerable buildings against earthquake as well. Combination of high seismicity of the country and vulnerability of buildings can lead to high levels of risk for the country, which shows the importance of risk management before and after events. A catastrophic event such as a major earthquake can result in loss of life and serious damage to buildings and their contents, which Iran has experienced many of them during Bam, Manjil and other big earthquakes in the past. Being prepared for a natural disaster is not a new problem. More-developed countries, governments, individuals and corporations around the world are aware of the fact that they need to be prepared against catastrophic events; however, they do not often take the necessary steps to prepare for a disaster. Only after a big disaster occurs, they recognize the importance of preparing for these types of extreme events and implication of disaster risk management tools. This is a bigger issue in developing countries where there is not enough financial resources or lacking a comprehensive risk management plan in place to manage these risks. In general, there are two approaches in managing catastrophic risks, risk distribution and risk mitigation. The main focus of this paper is on risk distribution. In order to assess available financial resources to cope with earthquake losses, we developed risk distribution tools which also take the financial vulnerability of the people and the region into account. These tools are earthquake insurance systems by using excess of loss insurance mechanism in which we could look at different layers of risk and risk management strategy associated with them. An insurer provides protection to residential and commercial property owners for losses resulting from natural disasters. Losses from natural disasters can have a severe impact on an insurer’s financial condition. Owners of commercial and residential structures on the other side, have a range of risk management strategies from which to choose. They can reduce their risk by retrofitting a structure to withstand earthquake loading, transfer part of their risk by purchasing some form of insurance, and/or keep and finance their risk. The ways in which particular individuals decide to manage risk is often a function of their perceptions. Many homeowners do not take action even when the risk is abundantly clear and loss-reducing measures are available. It is often the case that these homeowners feel that a disaster will not affect them. This shows the high importance of the acceptance of these risk management approaches by the society and the need to make people aware of their risk and providing incentives for them. The other important factor in every insurance system is affordability of earthquake premiums for people that is crucial in establishment and stability of the insurance system in the society which is investigated in this research. Probabilistic approach used here to assess the risk, shows a big difference between insurance premiums in Iran at the moment and risk-based premiums calculated in this research. This emphasizes the importance of incorporating the real risk assessment in decision making before and after catastrophic events. Catastrophe models are playing an important role in managing the risk of natural hazards through the establishment of risk-based insurance rates. These rates provide price information and economic incentives to mitigate and manage risks from low probability events that otherwise would be ignored until the disaster has occurred. The paper concluded by discussing the essential need to the use of catastrophe models for rate-setting purposes and also the importance of public-private partnership of the people and government and insurance companies in managing catastrophic events. Finally, the essential need to risk mitigation actions for very vulnerable assets and the need to get help from reinsurance and governmental help in the process of catastrophe risk management is shown here.

    Keywords: Vulnerability of Structures, Earthquake Risk Distribution, Earthquake Risk-Based Premiums, Affordability of Earthquake Premiums
  • Adel Faraji, Hamid Zafarani *, Farrokh Parsizadeh Pages 157-169

    This paper examinesand evaluates the knowledge of Babol citizens about the region seismicity and their readiness to deal with this situation. A questionnaire was distributed among the people of the city to gain awareness of the earthquake, their urgent needs, their behavior during the earthquake, their preparedness and the most common educational method, and receiving and transmitting earthquake concepts, etc. The 426 questionnaires were randomly distributed, consisted of those aged over 18 years old in different areas like universities and hospitals of the Babol. After completion of questionnaires, the responses were analyzed on SPSS software. According to the results, 62% of the respondents received educational materials about the earthquake, but 70% of them, did not consider Babol an earthquake-prone city or had no knowledge of its seismicity. Also, according to the results of the research, 72% of 18-25 years old have learned earthquake education materials by "school and university" and 21% through "radio, television, and internet", but 81% of this group did not consider Babol an earthquake-prone city or they had no knowledge of its seismicity. 46% of 34-41 age group and 41% of the age group "over 50 years old " also learned about earthquake education through "radio, television, and internet", but 66% and 58% of them did not consider Babol to be an earthquake-prone city or They did not know about it. One reason for these opinions in the minds of the people of Babol about this city seismicity is based on that they have a wrong definition of earthquake-prone or seismic since they were calling the city being earthquake-prone while experiencing earthquakes a few times a year or earthquake have been occurrences a few times in the region. The result shows that the earthquake-related training materials about the seismic condition of the city and make awareness should be as a priority. This reason can also be mentioned that many people have chosen "radio, television and internet" as an educational material source for receiving information about earthquakes. It seems that it is because of the television of the Islamic Republic of Iran, broadcasting information about the earthquake in general and nationally and, there is no detailed information provided about the region seismic status to the audiences. As a consequence, the new media can be used to raise public awareness about earthquake preparedness. In recent years, with the pervasiveness and availability of the internet and smartphones in society, the emergence of messaging applications and social networks, traditional means of communication have been marginalized. Therefore these phenomena should be used wisely to give a great chance to make public awareness and raise the level of that effectively. In conclusion, proper education and increase awareness about earthquakes should give as a priority. Education is expensive, but in societies without awareness and preparedness for damage and loss, after natural disasters such as earthquakes, it will cost governments hundreds of times more than education. We must always remember that prevention is better than cure. In this situation, the prevention is a right and, systematic training or education that this education should be attractive and enjoyable enough for young and adolescents. If a child is well educated, his family will benefit the most from that.

    Keywords: Earthquake, Awareness, Preparedness, Behavior Pathology, Babol