PACIFIC CATASTROPHE RIS, ASSESSMENT AND FINA INITIATIVE TONGA SEPTEMBER 2011 COUNTRY RISK PROFILE: TONGA Tonga is expected to incur, on average, 15.5 million USD per year in losses due to earthquakes and tropical cyclones. In the next 50 years, Tonga has a 50% chance of experiencing a loss exceeding 175 million USD and casualties larger than 440 people, and a 10% chance of experiencing a loss exceeding 430 million USD and casualties larger than 1,700 people. BETTER RISK INFORMATION FOR SMARTER INVESTMENTS COUNTRY RISK PROFILE TONGA POPULATION, BUILDINGS, INFRASTRUCTURE AND CROPS EXPOSED TO NATURAL PERILS An extensive study has been conducted to assemble a 8 Tongatapu comprehensive inventory of population and properties at 0 100 200 klofa risk. Properties include residential, commercial, public and industrial buildings; infrastructure assets such as major ports, airports, power plants, bridges, and roads; and major crops, such as coconut, palm oil, taro, vanilla and m any others. Vavau li ngs Haaa Commrcia TABLE 1: H a d Summary of Exposure in Tonga (2010) b General Information: 0 2 Total Population: 103,000 Tongatapu me 2 4 8 GDP Per Capita (USD): 3,470 Eua Kilometers Total GDP (million USD): 357.5 175' 14 Asset Counts: 0 2 4 8 Residential Buildings: 30,156 Tua Kilometers Public Buildings: 1,594 Figure 1: Building locations. Commercial, Industrial, and Other Buildings: 3,001 0 0 Tongatapu All Buildings: 34,751 05 100 200 '2 Nuku'alofa, Hectares of Major Crops: 36,010 K Imr Cost of Replacing Assets (million USD): Buildings: 2,525 Infrastructure: 259 Vavau Crops: 32 o , e iy(,il oSD/km'2) m 0-0.25 =1-2.5 Total: 2,816 H apai 0.25-0.5=15-5 Government Revenue and Expenditure: 07/ - 1o.s 0-120 Total Government Revenue C Haapai Vava'u (Million USD): 81.8 0 (% GDP): 22.9% Total Government Expenditure 072 4 W (Million USD): 99.2 To nga Eua K (% GDP): 27.7% Figure 2: Buidn relcmnost density by village. Data assembled from various references including WB,ADB, IMF and The Secretariat of the Pacific Community (SPC). 2 The projected 2010 population was trended from the 2006 census using estimated growth rates provided by SPC. Table 1 summarizes population and the inventory of buildings, Mom infrastructure assets, and major crops (or "exposure") at risk as well as key economic values for Tonga It is estimated that the replacement value of all the assets in Tonga is 2.8 va billion USD of which about 90% represents buildings and 9% represents infrastructure. He'pa Kiometers Tongatapu Figures 1 and 2 illustrate the building exposure location and replacement cost distribution, respectively. The footprints of o p 4 0 Ha'apai Vavau about 28,000 of the approximately 35,000 buildings shown in Tongza 0 Km Figure 1 were digitized from high-resolution satellite imagery. More than 10,000 of such buildings, all in the main island of Tongatapu, and most near the vicinity of the nation's capital of To nga E -cme Nuku'alofa, were also field surveyed and photographed by a team of inspectors deployed for this purpose. Figure 3 displays Land Cover/Land Use the land cover/and use map that includes the location of majorTao crops. The data utilized for these exhibits was assembled, Other Plan.b.n Gras, Land OpenLand Seed Bay Wetand organized and, when unavailable, produced in this study. Figure 3: Land cover/land use map. September 2011 COUNTRY RISK PROFILE TONGA TROPICAL CYCLONE AND EARTHQUAKE HAZARDS IN TONGA 0-i Tongatapu The Pacific islands region is prone to natural hazards. Tonga 0 50 100 20Nuku'alofa is located south of the equator in an area known for the frequent occurrence of tropical cyclones with damaging Kloreters winds, rains and storm surge between the months of October and May. In the South Pacific region from the equator to New Zealand in latitude and from Indonesia to east of Hawaii in longitude almost 1,000 tropical cyclones with hurricane- force winds spawned in the last 60 years, with an average of about 16 tropical storms per year. Tonga was affected by devastating cyclones multiple times in the last few decades. 0 2 4 8 Haapai Vavau For example, tropical cyclones Isaac and Waka, in 1982 and To - Katapu 0 2 4 8 2001, caused 7 fatalities, destroyed the shelters of tens rs of thousands of people as well as much of the nation's 175'W 174'W agriculture crops and caused about 75 million USD in losses . 024 8 that crippled the local economy. Figure 4 shows the levels of Tonga Eua - Kuometer wind speed due to tropical cyclones that have about a 40% chance to be exceeded at least once in the next 50 years (100- 0 25 50 75 100 125 150 175 200 year mean return period). These wind speeds, if they were to occur, are capable of generating severe damage to buildings, Maximum Wind Speed infrastructure and crops with consequent large economic Figure 4: Maximum 1-minute sustained wind speed (in miles per hour) with a 40% losses. chance to be exceeded at least once in the next 50 years (1 00-year mean return period). Tonga is situated along one segment of the Pacific "ring of024 8Togtp fire," which aligns with the boundlaries of the tectonic plates. -L! -- Togtp These tectonic plate boundaries are extremely active seismic 0 50 100 200 Nukualofa zones capable of generating large earthquakes and, in some E: K lometers cases, major tsunamis that can travel great distances. In 1977, a magnitude 7.2 earthquake violently shook the southern 4 islands of Tonga caused considerable damage to structures. ; Vavau A recent and tragic example is the offshore magnitude 8.1 Vv' earthquake in 2009, which generated a devastating tsunami . _ Hz'apai that killed 9 people and destroyed over half of the houses inH ai- the Tongan island of Niuatoputapu before hitting the shoresm of Samoa. Figure 5 shows that Tonga has a 40% chance in the 0 24 8 AHa'apai FV iV f7 next 50 years of experiencing, at least once, moderate to very 11Tongatapu ~I~ 0 2 4 8 Eua strong levels of ground shaking. These levels of shaking are ~ O4>1E 4 i-to expected to cause damage ranging from moderate to heavy 175- W 174 W to well-engineered buildings and even more severe damage ~ 0 2 4 8 tstructures built with less stringent criteria. T n a Eua Klmtr too nga RISK ANALYSIS RESULTS Perceived Shaking Not Felt Weak Light Moderate Strong Vy Strong Severe IViolent I Ex remel Moderateo Very To esti mate the risk profi le for Tonga posed by tropicalI cycl ones Potentlal Damage none none none Very Ight light Moderate Heavy HeaWy ldea and earthquakes, a simulation model of potential storms and Peakel.cm/sg) 2rt .714144040- -71-2 3-1 6-1 earthquakes that may affect the country in the future was Instrumental Intensity I 1-11I v I V Iv Vil constructed. This model, based on historical data, simulates ScalebasedouponVld. etral: 1999 more than 400,000 tropical cyclones and about 7.6 million Figure 5: Peak horizontal acceleration of the ground (Note: Ig is equal to the earthquakes, grouped in 10,000 potential realizations of the acceleration of gravity) that has about a 40% chance to be exceeded at least once in the nxt 5 yeas (10-yea meaKretunmpeiod) next year's activity in the entire Pacific Basin. The catalog of thnet5yar(I0-armnrtunpio) simulated earthquakes also includes large magnitude events in South and North America, Japan and the Philippines, which could generate tsunamis that may affect Tonga's shores. September 2011 COUNTRY RISK PROFILE TONGA The country's earthquake and tropical cyclone risk profiles are derived from an estimation of the direct losses to buildings, 0 Tongatapu infrastructure assets and major crops caused by all the 0 5 100 200 Nukualofa simulated potential future events. The direct losses include the cost of repairing or replacing the damaged assets, but do not include other losses such as contents losses, business interruption losses and losses to primary industries other than agriculture. The direct losses for tropical cyclones are caused by wind and flooding due to rain and storm surge, = 0 while for earthquakes they are caused by ground shaking 025-005 025 05 :, r = 0.05- 0.075 0.5-. and tsunami inundation. After assessing the cost of repairing 0 or rebuilding the damaged assets due to the impact of all the Tongatapu rapai P avau sim ulated potential future events, it is possible to estimateEu ;NU MI in a probabilistic sense the severity of losses for future catastrophes. 0 2 E K The simulations of possible next-year tropical cyclone and earthquake activity show that some years will see no storms Figure 7: Contribution from the different villages to the average annual loss for tropical or earthquakes affecting Tonga, while other years may see one or more events affecting the islands, similar to what has 0 Tongatapu happened historically. The annual losses averaged over the 0 5L0 0 Nuku'alofa, many realizations of next-year activity are shown in Figure lClometers 6 separately for tropical cyclone and for earthquake and tsunami, while the contributions to the average annual loss from the different villages are displayed in absolute terms !2 in Figure 7 and normalized by the total asset values in each village in Figure 8. Figure 8 shows how the relative risk varies H / 0 by village across the country. O/ - 0. . - 9%6 0.8 %-3 Tropical Cyclone Earthquake 0 0 apai Vavau Average Annual Loss = 9.5 million SD Average Annual Less = 6.0 million USID Tlne t 0.8%135 0.1%,K m * Buildings m Busildings17 W Cash Crops aCash Crops A t_ 0 lnfrastructure lnfrastructure 7.6% 86.4% IlEua Figure 6: Average annual loss due to tropical cyclones and earthquakes (ground Figure 8: Contribution from the different villages to the tropical cyclone and earthquake shaking and tsunami) and its contribution from the three types of assets. (ground shaking and tsunami) average annual loss divided by the replacement cost of the assets in each village. The same risk assessment carried out for Tonga was also performed for the 14 other Pacific Island Countries. The 11A 100 values of the average annual loss of Tonga and of the other 10 14 countries are compared in Figure 9. a In addition to estimating average risk per calendar year, another way of assessing risk is to examine large and 60 0 - rather infrequent, but possible, future tropical cyclone and -7040 earthquake losses. Table 2 summarizes the risk profile for Tonga in terms of both direct losses and emergency losses. The former are the expenditures needed to repair or replace the damaged assets while the latter are the expenditures that the Tongan government may need to incur in the .) o q, Z aftermath of a natural catastrophe to provide necessary b 4 s' relief and conduct activities such as debris removal, setting 411N up shelters for homeless or supplying medicine and food. The emergency losses are estimated as a percentage of the Figure 9: Average annual loss for all the 15 Pacific Island Countries considered in direct losses, this study. September 2011 COUNTRY RISK PROFILE: TONGA Table 2 includes the losses that are expected to be exceeded, In addition to causing damage and losses to the built on average, once every 50, 100, and 250 years. For example, environment and crops, future earthquakes and tropical an earthquake and tsunami loss exceeding 154 million cyclones will also have an impact on population. The same USD, which is equivalent to about 43% of Tonga's GDP, probabilistic procedure described above for losses has been is to be expected, on average, once every 100 years. In adopted to estimate the likelihood that different levels of Tonga, tropical cyclone losses are comparable to losses due casualties (i.e., fatalities and injuries) may result from the to earthquake ground shaking and tsunami. The latter, future occurrence of these events. As shown in Table 2, our however, remain potentially catastrophic events. model estimates, for example, that there is a 40% chance in the next fifty years (100-year mean return period) that A more complete picture of the risk can be found in Figure one or more events in a calendar year will cause casualties 10, which shows the mean return period of direct losses in exceeding about 600 people in Tonga. Events causing 2,000 million USD generated by earthquake, tsunami and tropical or more casualties are also possible but have much lower cyclones combined. The 50-, 100-, and 250-year mean return likelihood of occurring. period losses in Table 2 can also be determined from the curves in this figure. The direct losses are expressed both in TABLE 2: Estimated Losses and Casualties Caused by Natural Perils absolute terms and as a percent of the national GDP. Mean Return Period AAL 50 100 250 __________________________________________________(years) 500 Risk Profile: Tropical Cyclone 400 Direct Losses S _ ~ -- - -(Million USD) 9.5 78.7 126.0 21. 00 (% GDP) 2.7% 22.0% 35.2% 59.5% C--- EQ 0J 02 00 Emergency Losses 100__ T (Million USD) 2.2 18.1 28.9 48.9 * Q(% of total government 2.2% 18.2% 29.1% 49.3% 0 expenditures) 0 100 200 300 400 500 600 700 800 900 1,000 Mean ReturnPeriod(years) Casualties 10 87 134 209 Risk Profile: Earthquake and Tsunami 150% Direct Losses 125% (Million USD) 6.0 76.3 1542 280.1 100% ------0% (% GDP) 1.7% 21.4% 43.1% / 784% 75% Emergency Losses 0 (Million USD) 1.0 12.4 24.7 44.8 250% -TC+EQ (% of total government 1.0% 12.5% 24.9% 45.2% 25% --- Tcexpenditures) 0% _ _c--- EQasualties 24 245 575 1,160 0 100 200 300 400 500 600 700 800 900 1,000 Risk Profile: Tropical Cyclone, Earthquake, and Tsunami Mean Return Period (years) ___________________________________________________________Direct Losses Figure 10: Direct losses caused by either tropical storms or earthquakes that are (Million USD) 15.5 140.2 25.3 345.6 expected to be equaled or exceeded, on average, once in the time period indicated. (% GDP) 4.3% 39.2% 63.0% 96.7% Losses represetted in absolute terms atd normalized by GeP. Emergency Losses (Million SD) 3.2 28.1 41.8 63.6 (% of total government 3.2% 28.3% 42.1% 64.1% expenditures) Casualties 34 299 600 1,174 1 Casualties include fatalities a nd i njuries. September 2011 APPLICATIONS their fiscal balance. The earthquake and tropical cyclone The country risk profiles can support multiple applications hazard models also provide critical information for building that benefit both public and private stakeholders. In urban codes in terms of country-specific seismic and wind loads and development planning, planners can use the risk that buildings should be designed for to ensure adequate profile information to identify the best location of new shelter to the population. The risk information can also help development areas, evaluate how natural hazards may identify existing vulnerable areas and communities located shape their development, and to assess whetherthe benefits in or adjacent to these areas. This information can assist in of reducing the risk of natural events justify the costs of supporting more targeted intervention in community-based implementing the risk mitigating measures. In addition, disaster risk management and climate change adaptation the risk profiles can inform the development of disaster actions. In the occurrence of a natural disaster the database risk financing and insurance solutions and ex ante budget also provides extremely useful baseline data and information planning options to increase the financial resilience of the for conducting timely and effective post-disaster damage countries against natural disasters while maintaining assessments. SPC Secretariat of the Pacific Community Applied Geoscience and Technology Division (SOPAC) THE WORLD BANK * GFDRR Global Facility for Disste Reuc IanRe ve For information please visit http://pacrisk.sopac.org/ or contact pcrafi@sopac.org