Report on the Damage Investigation of
the 2001 Atico Earthquake in Peru

Koichi KUSUNOKI

Senior Researcher
Building Research Institute of Japan

April 2002

Copyright 2002 Building Research Institute of Japan

Chapter 1. Outline of the Investigation
1-1.

Background and purpose of the investigation

At 3:33 pm local time in Peru on June 23, 2001, (June 24, 5:33 am Japan time), a earthquake ofmagnitude 7.9 occurred near the coast of southern Peru, the epicentral region. This earthquake caused serious
damage, with 102 killed, 1,368 injured, and 11,043 houses destroyed in the vicinity of the provinces of Arequipa,
Moquegua and Tacna (Figures as of June 26, 2001).

Epicenter (http//www.disasterrelief.org/Disasters/010626peruquake2/)
On June 28, Japan delivered relief goods comprising 40 tents and 2000 blankets (specifically for cold
districts) to the severely damaged area to meet the immediate needs of the victims, followed on July 3 by
emergency grants-in-aid totaling US$500,000. The Japanese government also offered other countries’ aid agencies
bailout funds and relief goods. Many Japan-based and overseas NGOs were directly involved in providing onsite assistance.

1-2. Hypocenter determined by the U S Geological Survey
Date & Time:
Region:Epicenter:
Depth:
Magnitude:

JUN 23, 2001, 20:33:14.1
Near Coast of Peru
16.265 S, 73.641 W
33 km (fixed)
Ms 8.2, Mw 8.3, Mw 8.4 (Harvard)Chapter 2 A Site Investigation of the Earthquake-Damaged Region
2-1 Damage in the province of Arequipa
2-1-1 Outline

The province of Arequipa, located in the southern part of Peru, has a population of slightly over
1,000,000, of which 800,000 are concentrated in the capital, Arequipa City. Arequipa City is located at anelevation of 2,300 m at the foot of Mt. Misti, which produces a great deal of volcanic ash. In Arequipa City, thestricken population reached 790,000. Of the 160,000 dwellings in the city, 1,600 dwellings were seriously
damaged or collapsed, and 5,300 dwellings sustained minor damage. Sillar (white volcanic rock) dwellings
were extensively damaged, and brick dwellings suffered minor damage. The suburbs of the city alsosustained more serious damage than the central part. Socabaya District, a new residential area, sustained
damage caused by liquefaction.

2-1-2 Jorge Basadre Elementary School

This school, located in the southern part of Arequipa City, suffered damage to its building, which
was constructed in 1975 and consists of a one-storied reinforced concrete building 3 m in height. It is 7 spansin the longitudinal direction; the brick spandrel walls are about 2 m high and columns (25 cm x 35 cm, 30 cm
x 45 cm) have limited effective height. In the span direction there are 1-span brick walls acting as separators,
located at every other vertical plane in the structure. Major damage was observed in between the beamcolumn joints and the column capitals in the longitudinal direction as well as in the span direction. Thisbuilding escaped total collapse due to its being light and only one-storied. Insufficient shear reinforcement
and structural management of brick walls are considered problematic. There appears to be no problem withthe materials or construction.

Picture 2.1.2-1. Appearance of schoolhouse. Onestoried, brick spandrel wall.

Picture 2.1.2-2. Separation wall in span direction.
Damaged capital and beam-column joints. Shearin upper part of brick separation wall.

Picture 2.1.2-3. Shear failure of column.
Shortened column due to high spandrel wall.
Shear reinforcement intervals of 30 cm.

Picture 2.1.2-4. Damaged beam-column joint.
Supported with wood.

2-1-3 Liquefaction area in the ** District

Digging to a depth of 1 m creates a stream, since the water table is only 80-100 cm below the soil
surface. This district has the lowest elevation in Arequipa, and is close to a river. Several active volcanoes,
including Mt. Misti, are near this area, where granite is quarried. Dwellings leaned towards the river due tooutflow of soil following liquefaction.

Picture 2-1-3-1.
liquefaction.

Elevated

manholedue

toPicture 2-1-3-2. Full view of a building affected byliquefaction.

Picture 2-1-3-3. Separated boundary due to theinclination of the building caused by liquefaction.

Figure 2-1-3-4. Large cracks in the walls andfloors caused by inclination of the building.

2-1-4 Goyenecye HospitalThis hospital is located in the central area of Arequipa City. This is a one-storied sillar building.
Story height is 5-6 m. Wall thickness is about 80 cm. Major damage includes collapse of walls at the corners of
the building, damage to joints of upper openings in the longitudinal direction, and damage to parts wherebuildings are adjacent to each other. A beam in the span direction was added to the roof after the hospital wasdamaged by an earthquake in 1960.
Another newly constructed sillar building within the same lot was intact.

Picture 2-1-4-1. Appearance of the building.
Masonry, unique window shape. Beam added to
the roof.

Picture 2-1-4-2. Walls with damaged corners.

Picture 2-1-4-3. Damaged upper opening.
Damaged part where buildings are adjacent andat right angles to each other.

Picture 2-1-4-4. New masonry building.

2-1-5 San Augustin Hunter District Elementary School

Two schoolhouses were constructed in 1993 and 1995, respectively. The one constructed in 1993 isthree-storied and RC-framed. The other is one-storied and RC-framed. The latter was intact but the former
suffered slight damage. Although hollow bricks were used for nonstructural walls and spandrel walls in theformer schoolhouse, they had collapsed out-of-plane because no reinforcement was provided within thewalls. In both buildings, there were 3 cm wide slits around nonstructural walls revealing the insulating foam
inside. The columns were intact.

Picture 2-1-5-1. Full view of the building constructed in 1995. It was intact.

Picture 2-1-5-2. Full view of the schoolhouse
constructed in 1993.

Picture 2-1-5-3. On the near right, the hollow brickwalls of the second and third floors can be seen tohave collapsed.

Picture 2-1-5-4. Slit (black part) between the wall and the structural column.

Picture 2-1-5-5. Partial damage to nonstructural walls.

Picture 2-1-5-6. Classes are now being held in a temporary school building constructed on the playground.

2-1-6 Bridge to Centro

This masonry bridge crosses the river, which runs past the Centro (the central part of the old town)
in Arequipa City. Displaced stone blocks used for the balustrade, ripples in the road surface, and cracks on
the surface indicating extension in the crosswise direction can be seen. A loosened joint in the upper arch canalso be observed. The lowermost foundation part of the bridge was intact.

Picture 2-1-6-1. A bridge near Centro. Masonryarched bridge.

Picture2-1-6-2. Damaged balustrade. Outwardlydisplaced balustrade. Road surface showing
ripples.

Picture 2-1-6-1. Loosened arch. Loosening
between the surface of the arch and other stone
masonry was observed.

Picture 2-1-6-2. Crack in arch. Crack on thesurface of the arch. Some masonry blocks werecracked and displaced.

2-1-7 Cathedral

This cathedral, built of sillar blocks, is located at the front of Plaza de Armas. After the earthquake,one of the two towers collapsed and another closely escaped collapse. Loosening of the decorative arch due tothe earthquake was also observed. This cathedral had been repeatedly hit by previous earthquakes and was
repaired every time. The tower which escaped collapse was internally reinforced with steel beams after
collapsing in past earthquakes. Repairs have been initiated with the aid of the Spanish Government. There
was a "Danger" sign placed by INDECI (National Institute for Civil Defense).

Picture 2-1-7-1. Full view of the Cathedral. The left tower has collapsed. The right-hand tower, which justescaped collapse, under repair at the time, was reinforced with scaffolding.

Picture 2-1-7-2. Tower under repair.

Picture 2-1-7-3. Partially collapsed tower.

Picture 2-1-7-4. Decorative arches on both sides at
the front and loosened due to the earthquake,
under repair.

Picture 2-1-7-5. 'Danger' sign placed by INDECI.

2-1-8 Old store with sleeping quarters near the Centro

This three-storied building is located on the edge of the Centro (central old town) in Arequipa City.
The third floor of this building, which faces the road leading to the high bridge, is a store. The second floor
faces the road that passed under the bridge. The building was constructed of a more or less random mix ofsillar blocks and bricks. This building, called a "Tambo", was an inn for merchants. The building was old andthere is a plan to redevelop it.
The roof of the top floor and the roof arch between buildings fell to the ground. There were many cracks,
probably due to the earthquake, and loosening of joints.

Picture 2-1-8-1. Damage to the
top floor. The third floor,
facing the road Falling roof
eaves.

Picture 2-1-8-2. Appearance of the first and second floors. Masonryand brick. Limited damage due to the earthquake but the building is
structurally impaired.

Picture 2-1-8-3. Structure of the top floor roof.
Steel rail and sillar roof.

2-1-9 Fundo el Fierro Arequipa

Picture 2-1-8-4. Falling roof arch. Out-of-plane
deformation of masonry wall with falling arch.

This used to be a luxurious residence, but was rebuilt as a shopping center after being damaged in
the 1960 earthquake. Before reconstruction, it had two stories (basement level plus one floor). After the 1960
earthquake, the basement was filled in and the first floor rebuilt into a shopping center. Reconstruction was
conducted with the technical cooperation of SENCICO (National Service for Trading to the Construction
Industry). Only sillar blocks were used for reconstruction and the original structure was not changed. Thisbuilding was intact after the earthquake.

Picture 2-1-9-1. Full view of the one-storied shopping center.

Picture2-1-9-2. Sillar blocks were used as structural elements.

2-2 Damage in the province of Moquegua
2-2-1 Outlines

The province of Moquegua, which is located in the southeast part of the province of Arequipa, has
a population of nearly 150,000. About 67,000 live in Moquegua City. The province is located at an elevation of
1,400 m and has a mild climate. In Moquegua City, the stricken population reached nearly 30,000. Of theapproximately 17,000 dwellings, 4,300 dwellings suffered serious damage, including collapse, and 3,000
sustained slight damage. Adobe and sillar dwellings were extensively damaged; brick dwellings suffered
minor damage. The seriously affected San Francisco District is located on the top of a hill. Adobe dwellings,
occupied by low-income people, collapsed and some were killed by this earthquake. There is a plan to movethe residents in this District to the Pampa de Chanchan District in the suburbs. Liquefaction was observed in
Socabaya District.

2-2-2 Side wall of the river

The revetments of the river running through Moquegua City moved toward the river. It wasdifficult to ascertain from a distance; however, it can be assumed from the state of deformation that therevetment was constructed using gabions.

Picture 2-2-2-1. Deformation of the revetments.

Picture 2-2-2-2. Deformation of the revetments.

2-2-3 Simon Bolivar Elementary School

This school was established in 1711, and the schoolhouse was constructed in 1968. A collection ofbooks from the National Library was transferred to this school library.
I) A two-storied building
A two-storied building with a 6 x 1 span, with a structure in which brick walls are inserted into RC frames.
The span in the longitudinal direction is 6 m, the span direction has a length of 3 m, and the story height isabout 3.5 m. Columns on the first floor were shortened because they were limited in height by the
nonstructural wall (brick; 2 m in height). Shear failure and bond splitting were observed in these shortcolumns. The space between hoops was a very wide 25 cm.

Picture 2-2-3-1. Full view of the schoolhouse.

Picture2-2-3-2.

Damagedshortcolumn.

Picture 2-2-3-3. Short column. Wide space between lateral reinforcing bars.
II) A two-storied buildingThis two-storied building with 4 x 3 span has a structure of brick walls inserted into RC frames on the firstfloor and concrete blocks on the second floor. The story height is about 3.5 m. An engineer designed the firstfloor, and the second floor was homemade. Only the second floor suffered damage from the earthquake: there
were shear cracks on the wall in the span direction, and the roof supports collapsed.

Picture 2-2-3-4. Full view of the building.

Picture 2-2-3-5. Some of the roof supports
collapsed.

Picture 2-2-3-6. Damaged wall in the span direction.

2-2-4 Moquegua Private College

I) A three-storied building
Constructed in 1995 with a 7 x 2 span. Its stretcher has an anomalous span length. Most columns in thenorthern part of the first floor show shear failure. The ground had been dug up to inspect the foundations.

Picture 2-2-4-1. Appearance of thebuilding.

Picture 2-2-4-2. Damaged
column.

Picture 2-2-4-3. Soilinvestigation.

II) A four-storied building
Hollow brick walls are infilled into RC frames. The building was constructed in 1991 with a 9 x 1 span. Twospans to the north side had separated with expansion joint. It was thought that this separation resulted due tothe rigidity of the staircase. There was also a plan for the building to be extended upward. All partition walls
consisted of bricks. Shear failures were observed over doors on partition walls and in decorative beams incorridor walls. There was a window in the upper part.

Picture 2-2-4-4. Brick wall of the staircase.

Picture 2-2-4-6. Damaged short column.

Picture 2-2-4-5. Damaged long column.

Picture 2-2-4-7. Bar arrangement of the extended
part.

2-2-5 Adobe houses in the Centro District

In the Centro District, the damage rate of adobe buildings was no higher than that in the San
Francisco District. The damaged adobe houses were studded. There is no standard for adobe blocks; mostwere about 40-80 cm in size. Adobe walls are occasionally built two layers thick. INC (Peru’s National
Institute of Culture) has been conducting measurements of crack width in affected buildings for potential
widening. The walls of affected adobe walls collapsed mostly out-of-plane. Safety measures, such as thehooping of entire buildings, are required.

Picture 2-2-5-1. Street scene in Centro.

Picture 2-2-5-2. An adobe house saved fromdamage.

The collapsed house nearby was removed. The shape of the roof is called moginete-style. Bamboo-like lumber
is used.

Picture 2-2-5-3. A wall likely to fall out-of-plane.
The space widened to this extent in the week after
the earthquake.

Picture 2-2-5-4. Unit length of an adobe block.

Picture 2-2-5-5. Equipment for measuring increases in crack width, installed by INC.

2-2-6 Anterior wall of Plaza de Armas

This is the façade of a building constructed in 1792. It also suffered damage from the earthquake of1868, in which the back surface of the wall was removed. Damage from this earthquake was not too serious:
some of the sillar blocks in upper wall toppled. However, a bench is still in place beneath the part where somesillar blocks fell, and people still sit on the bench. This is extremely dangerous because of the risk of more
falling objects. We informed INC of this.

Picture 2-2-6-1. Full view of the wall.

Picture 2-2-6-2. Damage from the earthquake in1868. The back surface of the wall detached.

Picture 2-2-6-3. Falling upper wall.

Picture2-2-7 San Francisco District

2-2-6-4.

Displaced

upper

wall.

Approximately 80% of the buildings in this area are made of adobe, and most suffered some degreeof damage. This district contains a ravine. Houses on the sloping areas suffered more damage than on thebottom, probably due to soil amplification. The construction of dwellings had started from the upper slopes
and was extending to the bottom. No major damage was observed in non-adobe buildings. The inhabitants ofbuildings on this sloping area will be relocated to the Pampa de Chanchan District, which, although known tobe comprised of soft bentonite, is the only available district to which people can be moved since the otherpotential site for relocation, the San Antonio District, is already overcrowded. The Peru-Japan Center for
Seismic Research and Disaster Mitigation (CISMID) conducted a geological survey of the Pampa de Chanchan
and advised that adobe buildings should be limited to one story.

Picture 2-2-7-1. San Francisco District. It appears
to be ravine.

Picture 2-2-7-2. The size of adobe blocks used. The
adobe walls are thinner than those used in theCentro District.

Picture 2-2-7-3. Damaged adobe building. Walls
collapsed.

Picture 2-2-7-4. Greater damage seen in sloping
areas. Less damaged non-adobe buildings (two or
more storied). The blue buildings are temporary
dwellings.

2-2-8 The Pampa de Chanchan District

It is planned to move the population from the seriously damaged San Francisco District to thePampa de Chanchan district. However, its expandable clay soil is now under survey and measures are being
discussed. Problematic illegal occupancy has already occurred. Some people have already obtained homes inother districts and rent illegally occupied dwellings to others. Roads to the center of the city are underconstruction in the area.

Picture 2-2-8-1. Watercourse and illegal
occupancy.

Picture 2-2-8-2. Illegal occupancy.

2-2-9 A column holding a sunshade at the poolside of the El Mirador Hotel

Flexural failure of a column holding a sunshade at the poolside of the hotel occurred at its base.
Two columns had supported a roof slab. One column carried only a roof frame and the other carried a roof
slab; the latter column base suffered flexural shear failure. The reinforcement bars, which were jointed at theterminal hinge region, had buckled.

Picture 2-2-9-1. Full view.

Picture 2-2-9-3. The other column is
intact. Flexural cracks are observedin the beam.

Picture 2-2-9-2. A column supporting aroof slab. Flexural shear failure atcolumn base.

Picture 2-2-9-4. Column base. Reinforcements are jointed at
the terminal (right terminal).

Picture 2-2-9-5. Column base. Buckled main reinforcement.

2-3 Damage in the province of Tacna
2-3-1 Outline

The province of Tacna is located in the southernmost part of Peru, adjacent to Chile and Bolivia,
and has a population of nearly 280,000. Of these, nearly 250,000 people are concentrated in Tacna City. In
Tacna City, the stricken population reached 190,000. Of the 55,000 dwellings, 3,700 dwellings sustained
serious damage, including collapse, and 14,000 dwellings suffered slight damage. In the city, some adobebuildings collapsed. In the Ciudar Nueva District, a new residential area, the town hall, which is a reinforced
concrete building, suffered serious damage including shear failure of columns.

2-3-2 SENCICO Tacna Branch Office

The steel and R/C frames supporting the roof of the SENCICO workshop suffered damage. Theseframes became deformed out-of-plane together with the frame in the span direction, which exerts a tensile
force on the steel frame, resulting probably in removal of the steel frame at the joint with the concrete
member.

Picture 2-3-2-1. Gable of workshop.
Damage at the connection of the steel frame
spanning the right non-level part.

Picture 2-3-2-1. Damaged connection of steel framewith concrete member.

2-3-3 Ward office (Ciudar Nueva)

This building, which used to be a ward office and was scheduled to be used as a disaster refuge,
suffered damage from the earthquake. It consists of a first floor with concrete block walls infilled into RC
frames and a second floor with hollow brick walls infilled into RC frames. Construction engineers were not
involved in planning or design. The longitudinal direction comprises 4 spans, and the span direction has 3spans. The column size is 55 cm x 35cm, 6-D18, and Ø8@200 at the core. Some columns had no lateralreinforcing bars. There are no beams in the span direction. Damage was limited to the first floor. In particular,
the posterior columns of the building, which were short due to the high spandrel wall that occupied andlimited the space available for columns, showed occurrence of shear failure.

Picture 2-2-3-1. Appearance of the building. The
parapet on the rooftop toppled.

Picture 2-2-3-3. Shear crack in the wall. First floor:
concrete block wall. Second floor: brick wall.

2-3-4 Colegio Nacional Mariscal Caceres

Picture 2-2-3-2. Damaged CB wall and column.

Picture 2-2-3-4. Shear failure of theshort column. No lateral reinforcing
bar.

This is a two-storied schoolhouse with an 8 x 1 span, constructed in 1994. In the longitudinal
direction, which extends to the northeast, it has a span of 4 m, a length of 5 m in the span direction, and astory height of about 3 m. Deformed bars were also used as lateral reinforcing bars; the size of columns was
45 cm x 36 cm, width at the core measured about 20 cm, and the thickness of covering concrete was about 7.5
cm. There is a wall in the span direction every other span. Structural calculations may have been performed
for the walls; however, different diameters of reinforcement bars of columns and different types of reinforcing

hoops were used (round steel for parts where nonstructural walls were attached, and deformed bars for parts
without nonstructural walls). Concrete blocks were used for the walls.
A two-storied schoolhouse at the same site and facing in the same direction, which was constructed withassistance from Japan in 1990, suffered slight damage, including a shear crack in one column.

Picture 2-3-4-1. Full view of schoolhouse.

Picture 2-3-4-2. Shear failure of the column on thecorridor side resulting from shortened columns
due to limited vertical space, occupied by the
spandrel wall.

Picture 2-3-4-3. The length of the compressedcolumn was about 145 cm.

Picture 2-3-4-4. Shear failure of the column on thewindow side about 35 cm in width.

Picture 2-3-4-5. The space between the lateralreinforcing bars of the shortened column
measured about 12 cm.

Picture 2-3-4-6. Most columns on the window sideof the first floor show shear failure due to theirshortness.

Picture 2-3-4-8. A two-storied schoolhouse (1990)
Constructed with assistance from Japan.

Picture 2-3-4-7. The outside of column on thewindow side. This column has few lateralreinforcing bars.

Picture 2-3-4-9. Damaged column. A shear
crack was observed in one column.

Picture 2-3-4-10. Classes are now being conducted in a temporary structure.

2-3-5 Residential area

This residential area is located in the bottom of a landfilled valley. A three-storied building
suffered serious damage. Building workmanship was questionable because not all columns were vertical andthere are some honeycombs. Reinforcements were not attached to the walls of the staircase, and these walls
collapsed.
Some brick buildings were under repair work.

Picture 2-3-5-1. Damaged three-storied building.

Picture 2-3-5-2. Damaged wall of stairhall
The wall of the stairhall on the third floor
collapsed.

Picture 2-3-5-3. Concrete blocks.

Picture 2-3-5-4. Repair work nearby.

2-3-6 Hipolito Unanue HospitalThis is a national hospital with 5 floors and 1 basement level, constructed around 1950. Its structurefeatures an R/C frame with CB wall and several brick walls. It sustained minor damage, including slightcracks in nonstructural walls. After the earthquake, both public water supply and sewerage broke down, andthe gas supply facility was seriously damaged. The steam machine (used by the hospital for disinfection) was
also damaged and needed to be replaced, but the entire set of equipment, including buried piping, should infact be replaced. Normally, groundwater is pumped into an elevated water tank, but the pump did not work
after the earthquake. Even now, only outpatients and emergency patients are accepted, and the number ofhospital beds is very limited. The structure of the building itself is intact, but hard putty was used in thewindow frames, which increases the risk of shattering glass during the next earthquake.

Picture 2-3-6-1. Full view of the building.

Picture 2-3-6-2. Cracks between nonstructural
walls and structural member Crack (stairhall).

Picture 2-3-6-3. Broken window. Hard putty wasused.

2-3-7 Jorge Basadre Grohmann National University

Jorge Basadre Grohmann National University is home to 8,000 students in 14 faculties including 30
departments. The damaged FACF building was constructed in 1996. There are flexural shear cracks at thecolumn bases in the southwest corner and shear cracks at the joints between the upper and lower terminals
on the first floor. The inner pillars on the first floor have flexural cracks at the upper and lower ends.
A seismometer was supplied by JICA and installed by CISMID.

Picture 2-3-7-1. Damaged wall and beam-column
joints.

Picture 2-3-7-3. Damaged wall. Emergency
support.

Picture 2-3-7-2. Damaged capital.

Picture 2-3-7-4. The seismometer.