EERI Special Earthquake Report — June 2009

Learning from Earthquakes

The Mw 6.3 , , Earthquake of April 6, 2009

From April 17-24, a team made up versity of La Sapienza; Khalid The earthquake killed 305 people, of representatives of the Earth- Mosalam, Dept. of Civil Engineering, injured 1,500, destroyed or dam- quake Engineering Research Insti- UC Berkeley (PEER); H. John Price, aged an estimated 10,000-15,000 tute, the Applied Technology Coun- Curry Price Court, San Diego (ATC); buildings, prompted the temporary cil, and the Pacific Earthquake En- and Marko Schotanus, Rutherford & evacuation of 70,000-80,000 resi- gineering Research Center investi- Chekene, San Francisco. A separate dents, and left more than 24,000 gated the effects of the Abruzzo team from the Geo-engineering Ex- homeless. This event was the earthquake. The team was led by treme Events Reconnaissance Asso- strongest of a sequence that start- Paolo Bazzurro, AIR Worldwide ciation (GEER), led by Jonathan Stew- ed a few months earlier and num- Corp., San Francisco, and included art of UCLA, also contributed to this bered 23 earthquakes of Mw>4 David Alexander, CESPRO, Univer- report. between 03/30/09 and 04/23/09 sity of Florence; Paolo Clemente, (Figure 2), including an Mw 5.6 on The research, publication, and distri- ENEA Casaccia Research Centre, 04/07 and an Mw 5.4 on 04/09. bution of this report were funded by Rome; Mary Comerio, Dept. of the Earthquake Engineering Re- A total of 81 municipalities were Architecture, UC Berkeley (PEER); search Institute Learning from Earth- affected by the earthquake, and 49 Adriano De Sortis, Italian Dept. of quakes project, under grant #CMMI- of them were in the Prime Ministe- Civil Protection, Rome; Filip Filippou, 0758529 from the National Science rial Decree regarding damage of Dept. of Civil Engineering, UC Ber- Foundation. Mercalli-Cancani-Sieberg (MCS) keley (PEER); Agostino Goretti, Ital- intensities VI-X. (Note that in this ian Dept. of Civil Protection, Rome; Introduction range of intensities, the Modi- Mersedeh Jorjani, architectural con- On Monday April 6, 2009 at 3:32 a.m. fied Mercalli Intensity [MMI], more servator, San Francisco (ATC); Fab- widely used in the U.S., can be rizio Mollaioli, Dept. of Structural local time, an Mw 6.3 earthquake with computed as IMMI = 5/6 IMCS, as re- and Geotechnical Engineering, Uni- shallow focal depth (10 km) struck central Italy in the ported by Decanini et al., 1995). vicinity of L’Aquila, a The population of L’Aquila includes city of about 73,000 14 surrounding boroughs such as people that is the Onna, Paganica, and Tempera (see capital of the Abruzzo Figure 3). The combined population region (Figure 1). of the 48 other towns listed in the

Figure 2. Characteristics of 23 earthquakes above Mw4 from Figure 1. The epicenter of the Abruzzo event. 3/30 to 4/23 (Italian National Institute of Geophysics and Vulcanology).

 EERI Special Earthquake Report — June 2009

basin bounded by predominantly NW-SE-striking and SW-dipping active normal faults (Blumetti, 1995; Bagnaia et al., 1996). Downtown L’Aquila is set on a fluvial terrace that forms the left bank of the Aterno River (De Luca et al., 2005). The elevation of the terrace reaches 900 m above mean sea level (asl) in the northeastern part of the city and slopes down to 675 m asl in the southwest direction. The terrace ends at the Aterno River, which flows 50 m below. The alluvial deposits constituting the terrace are lower Quaternary in age, and are composed of breccias with limestone boulders and clasts in a The L’Aquila area and the locations of fatalities. Figure 3. marly matrix. Clast dimensions can range from centimeters to meters. official earthquake damage declara- Seismotectonic and Geo- tion is 60,352. The majority range logical Setting and Historical This kind of deposit is common in in size from 1,000 to 3,000 people, the Abruzzo region and may be re- with two larger towns of 5,000 and Seismicity lated to catastrophic alluvial events 8,500 inhabitants. The city of L’Aquila is located in the associated with landslides (Blu- metti, 1995). The deposits were The earthquake struck when most central part of the Apennine chain, a studied by Demageout (1965), who people were sleeping. The loca- thrust-belt that represents a margin of named them “megabrecce.” The tions of the 305 deaths can be seen a plate deformed during continental megabrecce represents a well- in Figure 3. The fatalities were con- collision between the African plate (to defined geological unit with flat top centrated in the 20-29 and over-70 which it belongs) and the Euroasian and bottom surfaces and a thick- age groups, though that does not plate that took place in the Cenozoic ness of some tens of meters, lying reflect the more balanced demo- 65 million years ago (Cavinato and on lacustrine sediments composed graphics of L’Aquila province. The De Celles, 1999; Devoti et al., 2008). mainly of silty and sandy layers and peak in the 20-29 group was due to The Apennines belong to a geody- minor gravel beds. The lacustrine the collapse of a student dormitory namic system that migrates from the sediments reach their maximum in downtown L’Aquila. Tyrrhenian to the Adriatic area (from W to E) in response to the flexural re- thickness (around 250 m) in the Many of the region’s cultural sites treat and subsequent sinking of the center of L’Aquila. In contrast, in were badly damaged or destroyed, Apulia platform. This unit is being sub- the Aterno River valley north of including Romanesque churches, ducted westward beneath the Apen- L’Aquila, the thickness of the sedi- palazzi, and other monuments dat- nines (Doglioni et al., 1990, 1991). ments is never greater than 100 m. ing from the Middle Ages and The city is located on a tectonic Renaissance. The historic centers of villages in the Aterno River valley southwest of L’Aquila — Onna, Paganica, and Castelnuovo — were essentially obliterated, with shaking intensities of up to X on the MCS Scale. Conversely, damage did not exceed MCS intensity VI nearly anywhere to the northwest of L’Aquila. This southeastward elongation of the damage pattern probably reflects a combination of rupture directivity and seismic litostratigraphic amplifi- Figure 4. Historical MCS macroseismic intensity of the major events near cation effects. L’Aquila since 1300.

 EERI Special Earthquake Report — June 2009

Table 1. Details from five stations with epicentral distance less than 20 km (source: Italian Dept. of Civil Protection).

Figure 4 shows the earthquakes Mw 6.3 event one of the best record- based only on Italian data (Scas- that have struck the city of L’Aquila ed earthquakes caused by a normal serra et al., 2009). and the villages around it since fault mechanism. Five stations, all on The 5%-damped spectra of the two 1300 (Stucchi et al., 2007; Rovida the hanging wall of the rupture, were horizontal directions produced by et al., 2009). L’Aquila has been se- located within 10 km of the epicen- USGS for the stations in Table 1 verely damaged at least five times ters, and all recorded a horizontal have shown, with the exception of in the last 700 years, specifically peak ground acceleration exceeding the AQK station, that the ground in 1315 (M ≈6.7), 1349 (M ≈6.5), 0.35g (Table 1). One station (AQM, w w shaking had mostly a high-frequen- 1461 (M ≈6.5), 1703 (M ≈6.7), and not included in the table) recorded 1g w w cy content (Figure 5). The ground 1915 (M ≈7.0). The 1461 event or more in the vertical and one horizon- w motion had also relatively short shows a damage distribution simi- tal direction, but went off scale above duration: 95% of the energy was lar to that of the April 6 earthquake, 1g in the second horizontal direction. released in 10 seconds or less. although it is shifted to the east by Its recordings are still subject to study; Finally, unprocessed data obtained a few km. they have not yet been released. from many stations show perma- Ground Motion Records The stations AQG, AQK, and AQM nent displacements of up to 15 cm. are on rock or stiff high-shear-wave- Fifty-six of the approximately 300 velocity (Vs) material, while AQA and Geotechnical Aspects digital strong-motion stations oper- AQV are on recent alluvium. Prelimi- The Geoengineering Extreme ated by Italian Strong Motion Net nary comparisons of ground motion Events Reconnaissance Association work (RAN) managed by the Italian intensity measures (IMs) from record (GEER) dispatched a team to the Department of Civil Protection (DPC) ings to prediction equations performed affected region within four days of recorded the main shock. In addi- by the GEER team show that high- the main shock. Their field survey tion, 142 broad-band stations re- frequency IMs attenuated more rapid- revealed no surface fault rupture, corded it. Fourteen stations are in ly with distance than is predicted by although they observed numerous the Abruzzo region, while the re- most empirical relations. This faster incidents of ground deformation. It maining ones are scattered in the attenuation is consistent with a recent- is possible that these were associ- Apennines mostly NW and SE of ly published modification of the next ated with co-seismic slip on shallow L’Aquila. This makes the Abruzzo generation of attenuation equations

Figure 5. Response spectra for 5% damping for the 5 stations in Table 1 that recorded >0.1 g and comparison with 2008 Italian Code Spectrum.

 EERI Special Earthquake Report — June 2009

beyond repair (see Figure 6). In other towns, such as , Santo Stefano, and Monticchio, ap- proximately 20-25% of the buildings in the center suffered extensive damage. The difference between the damage levels observed at lo- cations that are very close to one another, such as Onna and Montic- chio, and that have URM buildings of the same quality and character- istics, is most likely due to site am- plification effects (see the GEER report for details). Typical damage observed in L’Aqui- la consisted of generalized cracking of the masonry walls, especially between openings and in corners, leading to loss of the superficial plas- ter and sometimes causing local- ized collapses in poorly reinforced cornices and above window lintels. Figure 6. Devastation of poor-quality buildings in Paganica. Complete collapses of masonry structures in the historic center of faults not associated with the main well, although some failures were L’Aquila were rare, although the event. documented. severe damage observed in many rubble stone walls might trigger de- Damage patterns illustrate strong Historic Masonry Buildings molition of some this building stock. effects of site conditions. On a local In the Abruzzo region, as in most of Firefighter squads and the survey scale within suburban areas of Italy, the historic city centers are the team also observed failures of L’Aquila, GEER’s structure-to-struc- core of the built environment, account- floor slabs inside buildings, which ture mapping showed higher con- ing for 20% of larger cities like L’Aqui- rendered the structure unsalvage- centrations of damage in relatively la and 50% of smaller towns. In the able. These floor collapses might modern reinforced concrete struc- L’Aquila area, building began in the have been triggered by out-of-plane tures located on Holocene sedi- 13th century and continued to the deformation of walls and subse- ments than in similar neighboring modern era. The older unreinforced quent loss of support for the floor structures on Pleistocene sedi- masonry (URM) dwellings in the his- beams. ments. toric centers (usually 2-3 stories) are The superior performance of many On a broader scale, high damage built with stone and mortar walls; more of the masonry buildings in L’Aquila levels were seen in villages found- recent URM structures show a mixed can also be attributed to the better ed at least partly on relatively use of rubble-stone and clay bricks, quality of material (e.g., bigger size, young sediments (Onna, Castelnu- and in some instances concrete blocks. squared stones) and construction ovo); only light damage was visible In general, masonry buildings suffered that could be afforded by the richer in neighboring villages on bedrock a great amount of damage. families that have lived there histor- materials (Tussio, Monticchio). The team surveyed buildings in L’Aqui- ically. Several masonry buildings ob- Incidents of ground failure involved la and approximately 20 surrounding served within the historic center of disaggregated rock falls, seismic towns (of the 49 cities and towns in- L’Aquila had cross-ties (catene) sit- compression of poorly compacted cluded in the ministerial damage de- uated adjacent and parallel to the fills, minor deformations of levees cree). While L’Aquila had dramatic walls, with the purpose of limiting and flood control embankments, damage to late medieval, Roman- the out-of-plane deformation of the and slumping/spreading of sedi- esque, and Renaissance buildings buildings. These structures gener- ments around Lake Sinizzo. Earth and artwork, more widespread exten- ally performed well, displaying only and concrete dams at several res- sive damage was seen in smaller minor cracking in their walls and ervoirs in the strongly shaken re- towns such as Onna, Paganica, and corners. gion performed well. Earth-retaining Castelnuovo, where more than 50% The majority of buildings in the structures also generally performed of the historic centers were damaged countryside villages of lower in-

 EERI Special Earthquake Report — June 2009

Figure 7. Detail of 18th century wall- strengthening system, where no ties connect the beam to the wall. come populations used a construc- Figure 8. Collapse of a masonry building in Tempera with concrete ring beam tion technique (called a sacco) that retrofit. made them very vulnerable to earthquake damage. In this type of voids between the stone masonry diameter) timber into the wall with building, the gravity loads are car- and the scarcity of effective continuity wood or iron ties through the perpen- ried by thick unreinforced stone between the inner and outer wythes. dicular wall. In Paganica, we saw nu- with two outer wythes, often of Cross ties were also sometimes used merous examples of this approach, rounded stones that are poorly in these buildings with limited effec- where the first story was built after connected, if at all, by a limited num- tiveness because the deteriorated, the 1703 earthquake using the tim- ber of bond stones. Space between poorly maintained walls lacked suf- ber-and-ties technique, but 2nd and the two outer wythes is often filled ficient strength to carry the concen- 3rd floors were added in the 19th with an inner core of smaller rubble trated out-of-plane load imposed by century without ties, as the tech- masonry, poorly consolidated and the ties during the shaking. nique was forgotten (Figure 7). aggregated by a mixture of lime or After the last major earthquake in the Another interesting retrofit from the mud mortar. This results in walls region in 1703, attempts were made modern era was the use of a con- with limited vertical and lateral ca- to strengthen masonry walls by in- crete ring beam to stiffen the wall pacity because of the presence of serting a large (approximately 20 cm and prevent collapse. This was used

Figure 9. (a) Santa Maria del Suffragio, built after 1703, and (b) Santa Maria di Paganica, both in L’Aquila, lost the roof and cupola.

 EERI Special Earthquake Report — June 2009

forced with cross-ties and dead loads plus one third of the de- showed no damage. A church sign live loads. No specific provi- near Monticchio had its front sions for ductility were included. The façade separate from the lat- new code adopted in 2003 provides eral walls due the inability of only a minor increase of the design the wood connection beams peak ground acceleration (0.25g) in to keep the structure in place; L’Aquila, but includes strict guide- however, other parts of the lines to ensure that adequate ductil- façade tied with iron rods per- ity is achieved. Very few buildings formed well, showing no sep- in the area, however, have been aration of the structural ele- designed according to the new ments. code. Reinforced Concrete The older RC buildings in the region use smooth reinforcing bars, uncon- Buildings ventional lap splices, and in some The post-WWII residential cases, poorer quality construction buildings are of reinforced materials. The frames are almost al- concrete construction, typi- ways designed with no considera- cally 2-4 stories tall, but reach- tion for the layout of masonry infill ing up to eight in some cases. walls both in plan and elevation, as Figure 10. Roof and cupola collapse in the Most are multifamily condo- these are considered to be non- Santa Maria di Collemaggio Abbey in L’Aquila. miniums, and some have of- structural elements, and their exclu- The reinforced concrete ring beam did not fices or retail stores at the sion is thought to lead to conserva- prevent the collapse of the cupola. ground floor. For building de- tive design. The framing is filled in sign purposes, L’Aquila was consid- with one or two wythes of hollow on a number of churches (Figure ered seismic after the 1915 clay or concrete blocks, and some- 10). Unfortunately, this system earthquake, and buildings have been times finished with wrap-around clay proved to be ineffective, and many designed according to seismic provi- brick facades or stucco. Partitions structures, such as the building in sions ever since. are of thin hollow clay blocks. Figure 8, collapsed. The additional mass of the beam, the inconsisten- In the more modern building codes We found widespread damage to cy between the deformation of the issued in 1975 and revised in 1996, exterior infill walls and interior parti- beam and that of the walls, and the the province of L’Aquila was assigned tions, varying from small cracks to lack of positive connection between to seismic zone 2, and structures built collapse along with minor or no the beam and the masonry walls up to 2003 were designed for a hori- damage to structural elements. above and below are reasons that zontal acceleration of 0.23g; after the Several buildings completely lost were brought up to explain the application of appropriate code co- their masonry infill walls at lower generally poor results of this retrofit efficients, that translated into a design stories (Figure 11). This kind of technique. base shear of about 7% of the sum of damage extended to newer build- Many churches in the region expe- rienced partial failures of their walls and domes, fall of architectural ele- ments, out-of-plane wall failures, and cracking of bell towers and cor- ners (Figures 9 and 10). Some par- ticular cases of interest were the Chiesa di Santa Maria del Presepe in Paganica that suffered very little damage in contrast with the rest of the town, probably due to the rein- forcing corner plates and the proper anchorage of roof trusses into the walls. The Palazzo Dragonetti, built at the end of the 18th century and recently restored as a high-end Figure 11a/b. hotel, had its corners heavily rein- Typical damage to infill walls.

 EERI Special Earthquake Report — June 2009

In Pettino, northwest of L’Aquila, there were several pockets of rein- forced concrete structures that suf- fered significant damage. Among them were two soft-story collapses (Figure 13) and a large modern concrete structure with shear failure in several columns of its moment- resisting frame and the shear wall of its elevator core at the lower story (Figure 14). Since several columns remained intact, it is possible that torsional effects contributed to the unusual shear failure distribution, as the building is “L”-shaped in plan. Detail deficiencies included insuffi- cient column ties (i.e., excessive spacing and small section, which results in inadequate confinement), lack of cross ties, and splices with inadequate length. In summary, reinforced concrete Figure 12. Collapse of part of the Duca D’Abruzzi Hotel caused by a soft- buildings in the L’Aquila region be- story mechanism. The far part of the building was saved by a seismic sepa- haved, on average, fairly well, con- ration joint. sidering the limited seismic design requirements and the severe ground ings, including structures that have of 25cm or more. In some cases, shaking, often in exceedance of the been recently completed. In L’Aquila, there was also poor distribution of design level. From the perspective the team also observed about 15 fine aggregates and cement in the of the repair cost, however, rein- older low- to mid-rise apartment concrete, with a very porous core of forced concrete buildings showed buildings and one large hotel that disconnected larger aggregates. Short higher losses due to widespread suffered dramatic failures (Figure overlap of longitudinal rebar connect- extensive damage to masonry infill 12), generally due to a soft-story at ing columns between the upper and walls and internal partition walls the first or second story. At all the lower stories, short anchorage lengths (Figure 15). collapse sites, the team noticed the of the longitudinal beam reinforce- remains of column-beam connec- ment, and smooth rebars may have Public Buildings tions that showed insufficient trans- been responsible for the reduced The EERI team inspect- versal reinforcement in the form of 6 structural strength and ductility of Hospitals: ed the San Salvatore Hospital, the mm diameter stirrups, at a spacing these buildings.

Figure 13. Soft-story collapse in Pettino. Two of four Figure 14. Core shear wall with extensive structural almost identical structures collapsed. damage and failure in a modern RC building in Pettino.

 EERI Special Earthquake Report — June 2009

the ground floor showed nonductile detailing in the beam-column joints, the minimal confining reinforce- ment, and smooth rebars. A separa- tion in the concrete between the top of the pillars and the upper beams was also evident. On the other hand, the middle school in Pettino, a two-story reinforced concrete frame with infill brick walls completed in the 1980s, had a small amount of nonstructural damage. Similarly, the elementary school in Pianola, a two-story reinforced con- crete frame with infill brick walls built at the end of the 1990s, showed no structural damage. An internal nonstructural wall collapsed and a water heater fell down. The team surveyed two older ma- sonry schools. The first, the ele- Figure 15. The interior of the City Planning Offices in L’Aquila. Note that the mentary school in Coppito (two building exterior has very minor detectable damage. stories of about 5 m each, built in 1930), had been strengthened in main hospital in the L’Aquila prov- was able to inspect the exterior and 2003-04 by adding micro-piles in ince located in Coppito. This hospi- the interior of six schools in the area. the foundation. The school showed tal, which has 13 wings constructed The Pettino Elementary School, a moderate damage on the second from 1972-2000 to a 1967-era “in- two-story reinforced concrete frame story at one of the corners, but not termediate” seismic design, attract- with infill brick walls completed in on a first story where metal cross- ed a great deal of attention in the 1994, was seriously damaged and ties were present in the original media because it was shut down reached the verge of partial collapse design. some hours after the earthquake, (Figure 17). The damaged pillars on likely because of damage to a few concrete columns in three of its many buildings (Figure 16). Pa- tients were transferred elsewhere. Nonstructural damage was rela- tively moderate and limited. About 70%-80% of the hospital is expect- ed to be re-opened over the period June-October. The hospital staff reported neither deaths nor injuries due to earthquake damage at this site. Hospital emergency utilities operated as planned. Aside from structural column dam- age in three aforementioned rela- tively confined zones, the team could locate no other significant damage to the concrete frame. The nonstructural infill masonry likely contributed to resisting the earth- quake lateral forces and limited the frame deformation. Schools: The damage level in Figure 16. Column damage at hospital entry structure; no tie reinforcement is schools was varied. The EERI team evident.

 EERI Special Earthquake Report — June 2009

Figure 17. Extensive damage to the elementary school Figure 18. Partial collapse of the roof. in Pettino. The second elementary school in reinforced frames with concrete block age (Figure 19). The silos pounded L’Aquila, an old (1400-1700) poor- walls, and steel or light metal frames on the adjacent precast warehouse, quality masonry building formerly with precast panel walls. The damage partially crushing the concrete wall used as the hospital, was seriously observed was generally concentrated and leaving an imprint of impact. damaged and its roof partially col- in nonstructural elements (e.g., parti- The silos also crumpled at their lapsed. tions and ceiling tiles) and contents, bases. The undamaged sections although some structural damage to are being salvaged and reused. Industrial Structures beams and columns was observed. Lifelines The industrial building construction This was the case at the two-story re- in L’Aquila is similar to that found in inforced concrete frame Vibac chemi- Highways A24 and A25, connecting the United States: precast con- cal facility close to Paganica, engi- the Tyrrhenian and Adriatic coasts crete buildings with precast panels, neered in 2003 and constructed in of Italy, run through the area affect- 2006. The exterior was primarily glass ed by the earthquake. The A24 is window wall with hollow clay tile infill in many parts an elevated dual at the stair core and the back of the carriageway, consisting of simply building, adjacent to a one-story pre- supported single-span bridge seg- cast warehouse. We observed mul- ments on reinforced concrete piers tiple column shear failures, rupture of of varying height (Figure 20a). The the column tie reinforcement spaced A24 and A25 were closed for in- at 20 cm, cracking and falling of the spection following the earthquake, hollow clay tile infill, and collapse of but reopened to passenger vehicles the window wall glass. a few days later. In several locations, spans moved off their bearings (Fig- In the warehouse, a precast girder ure 20b/c); these stretches of high- collapsed along with one span of roof way were closed for repair. During slab (Figure 18). There did not ap- our visit, both highways had been pear to be any positive connection re-opened to all traffic, except for a of the precast girders to the exterior local part of highway A24 in L’Aquila, precast frame, and the exterior wall where repairs were still in progress appeared bowed, allowing the girder and traffic in both directions was to unseat. detoured. At a manufacturing plant in the same The only collapsed bridge structure facility we observed three tall steel was over the Aterno River along silos storing polypropylene beads that a secondary road to Fossa. The suffered damage. The three silos that bridge was of reinforced concrete Figure 19. Extensive damage at were full during the earthquake either construction with three continuous one silo. collapsed or suffered extensive dam- spans. The collapse of the bridge

 EERI Special Earthquake Report — June 2009

Figure 20. (a) Reinforced concrete highway viaduct that suffered movement of (b, c) bearings and misalignment of columns.

was likely induced by failure of the by the end of the day, except for the buildings. Gas and electricity pro- columns; we found a bridge of the one track from Rome to , vider ENEL contributed to emer- same design and vintage which al- which required repairs due to a mi- gency response and temporary so showed evidence of damage in nor landslide. Full service was active housing operations by providing the column hinge. Slight damage to by April 9, three days after the earth- mobile gas canisters to the field a few other bridges was also re- quake. hospital and the central command ported. center of the Department of Civil The airport at maintained Protection, and electrical service to A number of regional and provincial regular service during and after the shelters and tent camps. roads were partially closed, mainly event. The national air traffic authority as a result of earthquake-induced ENAV closed the air space in a radi- The most important damage to the land and rock slides and settle- us of 25 miles around the epicenter to water system was the pipe break ments. Driving on provincial route an altitude of 10,000 ft. to provide un- in the aqueduct from the Gran 38, from L’Aquila to Avezzano, we interrupted access to helicopters sup- Sasso, the main water supply of passed a few closed roads and porting emergency rescue operations. the area. A high pressure water were deviated at . Driving to main broke at the crossing of Utility networks for water, electricity Fossa, we noted various locations the Paganica fault, which experi- and phone services were all briefly where the steep embankment had enced a co-seismic movement in interrupted by the earthquake, but slid down, though was still retained the main event. There were also damage was localized. All services by the wire protection. Close to a number of pipe breaks in the were fully functional within a day after Fossa, we found the road closed distribution system, and many had minor repairs and reconfigurations. because of rock slides. Work was in to be repaired in order to provide Natural gas services to areas with progress during our visit to remove water to emergency shelters and significant damage were interrupted rock falls, restore embankments, temporary accommodations. A upon request of the fire department and repair paving. pipe break was reported as far as a safety precaution. Gas provider away as Pescara on the Adriatic The railways crossing the area af- ENEL successively checked over 250 coast. fected by the earthquake were in- miles of pipes for damage. Natural spected immediately after the event, gas and electricity remained off in Phone services were only briefly and most were reopened in time to areas of severe damage, like down- interrupted because of power have a minimal impact on service town L’Aquila and Onna, and several failure. Problems were typically (given the early hour of the earth- individual users remain disconnected solved by putting emergency gen- quake). All local lines were reopened because of severe damage to their erators into service. Our team

10 EERI Special Earthquake Report — June 2009 heavily depended on mobile phones buildings started from the less dam- case and high in the second, as for communication and coordina- aged neighborhoods and moved the ratio of serious to all injuries tion, and did not find any irregulari- gradually to the most damaged ones. was only 0.13, which is somewhat ties in available services. Areas farther from the epicenter are small by comparison with similar inspected only upon request. earthquakes elsewhere (commonly it Emergency Management About 1,500 inspectors were de- might be 0.15-0.25). and Building Inspections ployed every day to evaluate about The risk of injury and death was Given that the local prefecture build- 1,000 buildings daily. Each squad greatly increased by the collapse ing collapsed during the quake, the comprised three building profession- of URM walls, either as coherent Central Coordination Center of the als, at the beginning from the public slabs or in fragments; separation of emergency was run by the Depart- sector, but later from the private URM walls from roofs, with collapse ment of Civil Protection from the sector as well. Inspections were also of cornices and upper masonry; de- campus of the local police academy carried out by engineers from other tachment of roofs; ejection of infill school in Coppito, outside L’Aquila. EU countries (, Portugal, Slove- walls in RC buildings; and detach- Local management was delegated nia, Germany, France, and Greece) ment and collapse of the corners of to seven different centers in the sent by the Monitoring Information URM buildings. affected area. Center of the European Community. Given the complexity of failure pat- These teams were also joined by By April 8, a total of 2,250 firefight- terns in vernacular housing, it is a group of technicians sent by the ers, 1,500 army personnel, 2,000 reasonable to suppose that no sin- Ministry of the Russian Federation for policemen, and more than 1,000 gle self-protective behavior would Affairs of Civil Defense, Emergencies technical employees of the Abruzzo have been appropriate under all and Disaster Relief (EMERCOM). Regional office were working in the conditions. In heavily damaged region, as were 3,000 volunteers. As of May 2, about 24,000 buildings buildings, there was little to protect By then, 31 tent cities had been put had been inspected outside of the people from crush injuries or burial up to house 17,772 homeless peo- most damaged areas that were sub- by dust and rubble. Few cavities ple, and 171 hotels on the Adriatic jected to mandatory evacuation. were present in the rubble of col- coast were allocated to host an About 65% of the buildings were lapsed buildings. Running into the additional 10,000. Field hospitals green tagged (ready for occupancy) street clearly put people signifi- were also installed to provide first and 27% were red tagged (unsafe for cantly at risk from falling masonry emergency aid. The facilities for occupancy). The historic centers of or the collapse of stairways. In any the care and housing of homeless L’Aquila and other villages most dam- case, rapid egress was made dif- residents increased over time, with aged by the quake had not yet been ficult by doors that jammed as a about 1,700 private residences in inspected because of the high risk. result of racking distortion. the region opened for displaced The societal effects of any disaster people. Societal Impacts Analyses of worldwide patterns of can only really be assessed after On April 14, the first temporary earthquake casualties suggest that more than three weeks have school was opened in a tent city at 50-90% of deaths occur between passed, but some immediate ob- . On April 20, the midnight and 6 a.m. Studies in central servations can be made. As of University of L’Aquila reopened in America and Turkey highlight the May 3, 2009, over 65,000 people, a temporary structure at Coppito. importance of vernacular housing as approximately half of the population As of April 27, about 66,000 people a risk in nocturnal earthquakes or, in- of L’Aquila and surrounding areas, were in temporary shelters, 36,000 deed, whenever people are likely to were still in temporary housing (tent in 5700 tents, and 30,000 in 433 be at home (Glass et al., 1977; An- cities, hotels on the Adriatic coast, hotels and 1,600 private dwellings. gus, 1997; Rodriguez 2005). That is and private residences). On April 29, the mayor of L’Aquila equally true in Italy, where the only Nora Habed, a psychologist with declared that the people whose buildings more vulnerable to collapse SIPEM (Italian Emergency Psychol- dwellings were declared safe for (and on occasion fully occupied) are ogists), whose organization works occupancy could go back. ecclesiastical ones. with the Department of Civil Protec- The inspections of private houses In this earthquake, the overall death/ tion, has been counseling people started two days after the quake on injury ratio of 0.20 was relatively low, living in hotels on the coast. She April 8, after the teams had com- as 0.33 has been hypothesized for has found that many people would pleted public buildings such as hos- medium-to-large earthquakes. The prefer to stay in tent cities rather pitals and schools, and commercial case fatality rates of 0.17 overall and than in a hotel far away because and industrial sites. The systematic 0.60 for serious and critical (hospi- they would have more contact with inspections of all the residential talized) injuries are low in the first their neighbors and could do things

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such as cooking. Furthermore, naria Nova, II, 187-209. (Italy) – Input Data for Seismic some people are having difficulties Bertini, T. et al. (1989). La conca di Hazard Assessment. Natural Haz- in hotels, since they have to abide Fossa-S. Demetrio dei Vestini. In: ards 22: 225-270. by hotel rules and restrictions such CNR, Centro di Studio per la Geolo- Galadini, F. & P. Messina (2001). Plio- as curfew times. It is especially dif- gia Tecnica, ENEA, P.A.S.: Elementi Quaternary changes of the normal ficult for the elderly to adapt to this di tettonica pliocenico-quaternaria fault architecture in the Central type of life. As time passes and a ed indizi di sismicità olocenica Apennines (Italy). Geodinamica large portion of the population is nell’Appennino laziale-abruzzese. Acta, 14: 321-344. still without permanent housing, Società Geologica Italiana, 26-58. GEER (2009). Preliminary Report on people will increasingly feel the Bosi, C. & T. Bertini (1970). Geologia the Seismological and Geotechni- precariousness of their lives. della Media Valle dell’Aterno. Memo- cal Aspects of the April 6 2009 rie della Società Geologica Italiana, L’Aquila Earthquake in Central Acknowledgments IX, 719-777. Italy (http://research.eerc.berkeley. Significant contributions to this re- Boncio, P. et al. (2004). Defining a mod- edu/projects/GEER). port were provided by Silvio Calvi el of 3D seismogenic sources for Ghisetti F. & L. Vezzani (2000). Mo- (Consulting Engineer, Italy), Meh- Seismic Hazard Assessment appli- dalità di riattivazione, circolazione met Celebi (USGS), Giuseppe Di cations: The case of central Apen- dei fluidi e rottura sismica di al- Capua (Italian National Institute of nines (Italy). Journal of Seismology, cune delle principali faglie normali Geophysics and Vulcanology), Gia- 8, 407-425. nelle zone esterne dell’Appennino como Di Pasquale (Italian Dept. of Cavinato, G.P. & P.G. De Celles (1999). centrale. In: Galadini, F., C. Meletti Civil Protection ), Guillermo Franco Extensional basins in the tectonically & A. Rebez, Le ricerche del GNDT (AIR Worldwide), Antonella Gorini bimodal central Apennines fold-thrust nel campo della pericolosità sis- (Italian Dept. of Civil Protection), belt, Italy: response to corner flow mica (1996-1999). CNR-Gruppo Sandro Marcucci (Italian Dept. of above a subducting slab in retro- Nazionale per la Difesa dai Ter- Civil Protection), Chris Poland grade motion. Geology, 27, 955-958. remoti, Roma, p. 397. (Degenkolb Engineers), Holly Raz- De Luca, G. et al. (2005). Evidence of Ghisetti, F. & L. Vezzani (2002). Nor- zano (Degenkolb Engineers) and Low-Frequency Amplification in the mal faulting, transcrustal perme- Fabio Sabetta (Italian Dept. of Civil City of L’Aquila, Central Italy, through ability and seismogenesis in the Protection). a Multidisciplinary Approach Includ- Apennines (Italy). Tectonophysics, ing Strong- and Weak-Motion Data, 348: 155-168. Other colleagues also assisted the Ambient Noise, and Numerical Mod- team and provided valuable infor- Glass, R.I. et al. (1977). Earthquake eling. Bulletin of the Seismological injuries related to housing in a mation: Dario Rinaldis (ENEA), Society of America, 95: 1469–1481, Guatemalan village. Science 197: Guido Martini (ENEA), Tito Sano’ doi: 10.1785/0120030253 638-643. (formerly at ENEA), Fausto Marin- cioni (University of Marche, Italy), Decanini, L. et al. (1995). “Proposta QUEST (2009). Rapporto sugli effetti di definizione delle relazioni tra Roberto Tomasi (University of del terremoto aquilano del 6 aprile intensità macrosismica e parametri Trento, Italy), Peter Crosby (Crosby 2009. Rapporto INGV (http://www. del moto del suolo”. 7° Convegno Group), Susan Johnson (Crosby mi.ingv.it/eq/090406/quest.html). Nazionale: L’ingegneria sismica in Group), and Iunio Iervolino (Univer- Italia, Siena, 25-28 Settembre 1995, Rodriguez, M.E. (2005). Evaluation sity of Naples). pp. 63-72. and design of masonry dwellings in seismic zones. Earthquake Devoti, R. et al. (2008). New GPS con- Spectra 2(2): 465-492. Bibliography straints on the kinematics of the Rovida, A. et al. (2009). Terremoti Angus, D.C. (1997). Epidemiologic Appeninnes subduction. Earth storici nell’area colpita dagli assessment of mortality, building Planet Sci. Lett., doi: 10.1016/ eventi sismici dell’aprile 2009. collapse pattern, and medical j.epsl.2008.06.031. INGV Report (http://www.mi.ingv. response after the 1992 earth- Doglioni, C. (1990). The global tectonic it/eq/090406/storia.html). quake in Turkey. Prehospital and pattern. Journal of Geodynamics, Disaster Medicine 12: 222-234. 12, 1, 21-38. Stucchi et al. (2007). DBMI04, il database delle osservazioni mac- APAT (2006). Carta Geologica d’Italia Doglioni, C. (1991). A proposal of kine- rosismiche dei terremoti italiani alla scala 1:50.000 – Foglio n. 359 matic modelling for W-dipping sub- utilizzate per la compilazione del “L’Aquila”. S.EL.CA. Firenze ductions - Possible applications to catalogo parametrico CPTI04. Bagnaia, R., A. et al. (1992). Aquila the Tyrrhenian - Apennines system. Quaderni di Geofisica, Vol. 49, and subaequan basins: An exam- Terra Nova, 3, 4, 423-434. pp.38 (http://emidius.mi.ingv. ple of Quaternary evolution in Galadini F. & P. Galli (2000). Active it/DBMI04/). Central Apennines, Italy. Quater- Tectonics in the Central Apennines

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