EARTHQUAKE PROFILE The Iranian plateau has long been known as one of the seismically active areas of the world and it frequently suffers destructive and catastrophic earthquakes that cause heavy loss of human life and widespread damage. The I.R.Iran is located in the area of the mountain belt of Alp-Himalayas, which is the last and the youngest mountainous area in the world. The spreading of the Red Sea resulting in the movement of the Saudi Arabian desert towards Iran, the displacement of the Indian Ocean bed in the Oman region towards the northeast, and the movement of other lithosphere plates around Iran have caused circumstances that lead to disastrous earthquakes in Iran every so often, due to the release of energy produced by concentration of stresses in the direction of faults. Over 90% of the country is exposed to the Earthquake hazard (Figure 1). Figure 1-Seismic hazard map, I.R.Iran 1
Regarding DesInventar, totally, 3,455 earthquake events (52.7% of all records) were recorded in Iran for the period of 1986-2007, which led to 70,289 deaths, 140,078 injured, 371,033 damaged or destroyed buildings and 1,553,912 affected population. Table 1 indicates the 10 largest earthquakes in Iran for this period, sorted by numbers of killed. Two mega earthquakes happened in term of mortality and destruction, i.e. Rudbar-Manjil (1990) and Bam (2003) earthquake. Table 1- Ten largest earthquakes sorted by numbers of people killed, I.R.Iran, 1986-2007 Year Ostan Shahrestan Magnitude Killed Injured 1990 Gilan, Zanjan Rudbar, Manjil, Lushan Building damaged & destroyed Affected population 7.3 40,000 105,090 100,000 710,000 2003 Kerman Bam 6.3 26,271 22,739 55,000 267,628 1997 South Khorasan Ghaenat 7.3 1,700 2,600 12,800 72,000 1997 Ardebil Ardebil 6.1 965 2,600 22,000 38,600 2005 Kerman Zarand 6.4 612 1,621 -* - 2002 Ghazvin Bouinzahra 6.2 230 1,466 41,988-1997 North Khorasan Bojnurd 6.1 100 220 14,357 84,500 1989 Kohgiluyeh va Boyerahmad Boyerahmad 4.5 100 17-217 2006 Lorestan Dorud 6.0 63 2,000 52,261 161,418 2004 Mazandaran Nur 6.1 60 212 8,000 - * No valid data available. 2
Percent Figure 2 shows the frequency of earthquake events by magnitude on the Richter scale, recorded by DesInventar. 50.0 40.0 41.0 34.5 30.0 20.0 10.0 0.0 9.7 8.5 4.8 0.1 1.2 0.1 Missing 1.0-1.9 2.0-2.9 3.0-3.9 4.0-4.9 5.0-5.9 6.0-6.9 >=7.0 Richter scale Figure 2 Earthquake frequency by magnitude (Richter scale), recorded by DesInventar, I.R.Iran, 1986-2007 Figure 3 shows that earthquake occurrence was on an increasing trend from 1986 to 2007, mainly earthquakes with magnitude of 3.0-4.9 on Richter scale. Improvement of recording system could be the reason of the upward trend. No clear monthly trend was observed (Figure 4). 500 400 300 200 100 >=7.0 6.0-6.9 5.0-5.9 4.0-4.9 3.0-3.9 2.0-2.9 1.0-1.9 0 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Figure 3- Annual trend of earthquake occurrence by magnitude (on Richter scale), I.R.Iran, 1986-2007 400 300 200 100 >=7.0 6.0-6.9 5.0-5.9 4.0-4.9 3.0-3.9 2.0-2.9 1.0-1.9 0 January February March April May June July August September October November December Figure 4- Monthly trend of earthquake occurrence, I.R.Iran, 1986-2007 3
Percent During 1986-2007, earthquakes were responsible for 3347.0 deaths, 6,670.3 injuries, 16865.1 building damage or destruction, in average, per year. Compared to other natural hazards, during 1986-2007, earthquakes caused 94.9% of recorded mortality, 98.7% of injuries and 73.0% of building damaged or destroyed (Figure 5). 100 80 60 40 94.9 98.7 73.0 20 0 Death Injury Building damage Earthquake Other natural hazards Figure 5- Comparison death, injury and building damage or destruction caused by earthquakes and other natural hazards, I.R.Iran, 1986-2007 4
95% CI Death to Injury Ratio (DIR) Mean Death to Injury Ratio (DIR) was 1.2±2.4 with median of 0.1 (range 0.0-12.0), given assuming at least one injury for the events with at least one death. Figure 6 indicates mean and related 95% of DIR among different magnitudes of earthquakes. DIR reveals an upward trend with increasing the magnitude, except for magnitude of >=7 on the Richter scale that is related to Rudbar-Manjil earthquake (1990) with death toll of 40,000 and 105,000 injured. 3 2 1 0-1 -2 2.0-2.9 3.0-3.9 4.0-4.9 5.0-5.9 6.0-6.9 >=7.0 Magnitude (Richter scale) Figure 6- Earthquake-related Death to Injury Ratio (DIR), I.R.Iran, 1986-2007 5
By increasing the earthquake magnitude, number of death and Death to Buildings damage or destruction Ratio (DBR) increases (Figures 7 and 8). This is true about damage to buildings, except for magnitude of >=7 on the Richter scale that is related to Rudbar-Manjil earthquake (1990) with death toll of 40,000 and 100,000 building damaged or destroyed (Figure 6). It is worthy to mention that number of buildings damaged and destroyed due to Rudbar-manjil earthquakes varies up to two folds between two main sources of information, i.e. from 100,000 according to National Geoscience Database of Iran (NGDIR) to 200,000 according to Ministry of Housing. Figure 7- Death and building damage or destruction by earthquake magnitude, I.R.Iran, 1986-2007 6
Mean Death to Building damage Ratio (DBR).3.2.1 0.0 2.0-2.9 3.0-3.9 4.0-4.9 5.0-5.9 6.0-6.9 >=7.0 Magnitude (Richter scale) Figure 8- Earthquake-related Death to Building damage or destruction (DBR) by magnitude, I.R.Iran, 1986-2007 The highest number of death and building damage happened in the year of 1990 (Rudbar-Manjil earthquake), 1997 (Ardebil earthquake), 2003 (Bam earthquake) and 2006 (Lorestan earthquake). Comparison of DBR in Bam (2003, Mw 6.3) and Lorestan earthquakes (2006, Mw 6.0) shows how important is effective early warning and prompt reaction of the community. While Bam earthquake BDR was 0.48, Lorestan earthquake BDR was calculated as 0.012. Experts believe that the low mortality of Lorestan earthquake was related to on-time warning issued by Disaster Taskforce once pre-shocks jolted the area and the prompt reaction of people who evacuated their homes. Paying attention to pre-shocks was the valuable lesson that people had learned from Bam earthquake. 7
Figure 9- Annual trend of death and Building damaged and destroyed caused by earthquakes, I.R.Iran, 1986-2007 Comparing the number of mortality between the periods of 1986-1996 and 1997-2007 reveals 25% reduction, from 40,196 to 30,093. While buildings damage shows 132% increase in trend, from 111,459 to 259,574 (Figure 10). There is no doubt that the country needs to continue enhancement of mitigation measures in housing and building construction sector, but effective warning in Lorestan earthquake (2006) was a valuable experience that saved thousands of lives. Otherwise we witnessed, at least a flat trend of mortality between two time periods. 8
Figure 10- Comparison of earthquake-related death and building damage between 1986-1996 and 1997-2007, I.R.Iran Death per 10,000 populations varied among provinces from 0.0 to 8.35. Gilan (8.35/10,000 inhabitants), Kerman (5.24/10,000 inhabitants) and South Khorasan (1.22/10,000 inhabitants) experiences the highest mortality due to earthquakes in the period of 1986-2007. Ghom was the only province with no death. 9
The highest numbers of buildings damage or destruction were observed in Gilan (27.4%), Lorestan (18.2%), Kerman (15.8%) and Ghazvin (11.3%). Figure 11- Frequency, death & injury per 10,000 inhabitants and building damaged or destroyed by earthquakes at province level, I.R.Iran, 1986-2007 Frequency of earthquake occurrence, number of death, injury and buildings damage or destruction at Shahrestan level is shown in Figure 12. 10
Figure 12- Frequency, death & injury per 10,000 inhabitants and building damaged and destroyed by earthquakes at Shahrestan level, I.R.Iran, 1986-2007 Annex Tables 11
Table A1- Provincial distribution of death, injury and building damaged and destroyed caused by earthquakes, I.R.Iran, 1986-2007 Province No of Death % No of Injury % No of Building damage Ardebil 965 1.4 2600 1.9 22400 6.0 West Azarbayjan 0 0.0 0 0.0 0 0.0 East Azarbayjan 5 0.0 105 0.1 0 0.0 Bushehr 2 0.0 60 0.0 854 0.2 Chaharmahal va Bakhtiyari 5 0.0 53 0.0 902 0.2 Esfahan 0 0.0 3 0.0 15 0.0 Fars 62 0.1 603 0.4 8047 2.2 Ghazvin 230 0.3 1466 1.0 41988 11.3 Gilan 40003 56.9 105106 75.0 101623 27.4 Golestan 0 0.0 63 0.0 658 0.2 Hamedan 2 0.0 0 0.0 0 0.0 Hormozgan 13 0.0 112 0.1 4447 1.2 Ilam 0 0.0 0 0.0 520 0.1 Kerman 26896 38.3 24419 17.4 58646 15.8 Kermanshah 4 0.0 71 0.1 11038 3.0 South Khoransan 1712 2.4 2629 1.9 18550 5.0 Khorasan-e-Razavi 1 0.0 15 0.0 2398 0.6 North Khorasan 100 0.1 220 0.2 14357 3.9 Khuzestan 0 0.0 200 0.1 6179 1.7 Kohgiluyeh va Boyerahmad 124 0.2 84 0.1 1589 0.4 Kurdestan 0 0.0 0 0.0 40 0.0 Lorestan 69 0.1 2056 1.5 67350 18.2 Markazi 0 0.0 0 0.0 0 0.0 Mazandaran 60 0.1 213 0.2 8461 2.3 Ghom 0 0.0 0 0.0 0 0.0 Semnan 12 0.0 0 0.0 371 0.1 Sistan va Baluchestan 15 0.0 0 0.0 400 0.1 Tehran 9 0.0 0 0.0 0 0.0 Yazd 0 0.0 0 0.0 200 0.1 Zanjan 0 0.0 0 0.0 0 0.0 Total 70289 100.0 140078 100.0 371033 100.0 % 12
Table A2- Annual distribution of of death, injury and building damaged and destroyed caused by earthquakes, I.R.Iran, 1986-2007 Year 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Death per 10,000 inhabitants 0.03 0.02 0.02 2.40 183.77 0.01 0.07 0.47 0.13 0.00 0.00 36.24 0.24 0.11 0.00 0.00 2.18 112.82 Death % Injured % Building % 10 0.01 14 0.01 285 0.08 4 0.01 1 0.00 797 0.21 4 0.01 31 0.02 1,355 0.37 117 0.17 35 0.02 107 0.03 40,002 56.91 105,186 75.09 100,416 27.06 2 0.00 61 0.04 47 0.01 6 0.01 54 0.04 500 0.13 24 0.03 52 0.04 2,345 0.63 27 0.04 358 0.26 4,750 1.28 0 0.00 11 0.01 842 0.23 0 0.00 0 0.00 15 0.00 2,770 3.94 5,495 3.92 56,607 15.26 27 0.04 118 0.08 2,776 0.75 35 0.05 150 0.11 5,282 1.42 1 0.00 15 0.01 100 0.03 1 0.00 10 0.01 60 0.02 236 0.34 1,573 1.12 48,307 13.02 26,274 37.38 22,742 16.24 62,048 16.72 2004 0.21 60 0.09 212 0.15 8,129 2.19 2005 2.60 623 0.89 1,873 1.34 8,701 2.35 2006 0.39 66 0.09 2,014 1.44 67,261 18.13 2007 0.00 0 0.00 73 0.05 303 0.08 Total 341.71 70,289 100 140,078 100 371,033 100 13