EERI Special Earthquake Report — December 2011

Learning from Earthquakes

The Mw 5.8 Earthquake of August 23, 2011

After the Mw 5.8 earthquake of social disruptions up and down the The epicenter of the August 23 August 23, 2011, EERI assembled East Coast that lasted from several quake was 8 km from Mineral, a team of East Coast EERI mem- hours to some months. The quake Virginia, 61 km from Richmond, bers to document various aspects caused widespread interruptions to and 135 km from Washington, of the event. Co-leaders were communications and transportation D.C. (Figure 1). A network of James Beavers, a consulting struc- systems, numerous school closings in seismographs installed following tural engineer from Knoxville, Ten- the epicentral area of Louisa County, the August 23rd main shock has nessee, and William Anderson, a other closures in the greater Wash- enabled accurate location of many sociologist and an EERI Board ington, D.C., area, and an automatic . The aftershocks define member from Washington, D.C. shutdown of the North Anna Nuclear a 10-km-long, N28°E striking, Other team members included Power Plant. The earthquake is a 45°ESE dipping at between Matthew Eatherton, Virginia Tech; noteworthy reminder that communi- 2.5 and 8 km depth, in good agree- Ramon Gilsanz, Gilsanz Murray ties on the East Coast are not pre- ment with the focal mechanism of Steficek Inc; Frederick Krimgold, pared to cope with a major earth- the main shock. The locations of Virginia Tech; Ying-Cheng Lin, quake, and that steps could be taken aftershocks do not correspond to a Lehigh University; Claudia Marin, to improve their readiness and in- previously identified fault; previous, Howard University; Justin Marshall, crease loss reduction efforts. smaller, instrumentally recorded Auburn University; Jelena Pantelic, earthquakes in the zone have had the World Bank; and James Ricles, Seismology diverse focal mechanisms over Lehigh University. Marshall partici- an area with a length and width of The Mw 5.8 (USGS) earthquake re- pated remotely by mapping struc- about 120 km, rather than align- sulted from reverse faulting at shallow tural damage. Additional material ment in a pattern that might sug- depth (estimated at 6 km) on a north- was furnished by members of the gest a single causative fault. northeast-striking plane within a pre- Geotechnical Extreme Events Re- viously recognized seismic zone: the Figure 1 shows the regional dis- connaissance (GEER) Association Central . This tribution of intensities associated team: Russell Green, Virginia Tech; zone has produced James Martin, Virginia Tech; Sissy small and moder- Nikolaou, Mueser Rutledge Con- ate earthquakes sulting Engineers; and Sam Lasley, since at least 1774, Virginia Tech. Other contributors to the previous most this report included Jeff Munsey, damaging shock Tennessee Valley Authority, and a having been in team of social scientists from the 1875. That quake Disaster Research Center at the predated the inven- University of Delaware: Yvonne tion of effective Rademacher, Alex Greer, Laura seismographs, but Keeley, James Kendra, Benigno its felt effects and Aguirre, and Lucia Velotti. area suggest that it Unless otherwise indicated, photos had a magnitude of in this report were taken by EERI about 4.8. It shook team members. bricks from chim- neys, broke plaster Introduction and windows, and overturned furni- The Mw 5.8 earthquake that struck central Virginia at 1:51 p.m. local ture at several lo- time on August 23, 2011, caused cations. An M4.5 no deaths and few injuries, but did earthquake on De- damage buildings and other struc- cember 9, 2003, tures within a 100-mile radius of also caused minor the epicenter. Perhaps its biggest damage. Figure 1. Epicenter and intensity map made from effects were the business and 148,281 respondents to USGS DYFI site.

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Figure 2. Acceleration response spectrum with 5% damping recorded at the North Anna Nuclear Power Plant for periods up to 5 sec (left) and isolating low-period range (right) (adapted from Dominion, 2011).

with the earthquake, as estimated Regional Geology at earthquake depths, but numer- from data contributed to the USGS ous smaller or deeply buried faults “Did You Feel It?” (DYFI) web site. The region is very old, with bedrock remain undetected. Accordingly, Reports of the shock came in from formed more than a billion years ago few, if any, earthquakes in the seis- most zip codes within 800 km of the and a complex surficial geology that mic zone can be linked to named epicenter, and additional observa- bears the imprints of continental colli- faults, and it is difficult to determine tions came in from zip codes at sions, long-dead mountains, and for- whether a known fault is still active greater distances (Figure 1). Ac- gotten seas (Mittelbach & Crewdson, and could slip and cause an earth- cording to the USGS, the large felt 1998). The regional geology is char- quake. area is not unusual for an eastern acterized by a distinct “fall line” that U.S. shock; east of the Rockies, an separates inboard bedrock (the earthquake may be felt over an area province) from the out- ten times larger than that for a simi- board Atlantic Coastal Plain. lar magnitude earthquake on the The fall line runs southwesterly West Coast. from the District of Columbia- Montgomery County boundary A maximum intensity of VII is esti- near Silver Spring, , mated from DYFI data, when obser- across the Potomac River north vations are averaged over zip code of Roosevelt Island (Figure 3). regions. However, field observa- tions indicate that an area in rural Most bedrock beneath central Louisa Country close to the causa- Virginia was assembled as tive faulting had shaking correspond- continents collided to form a ing to Modified Mercalli Intensity supercontinent about 500-300 VIII; the average DYFI intensity is million years ago, raising the VII for the entire 500-km² zip code . The region in which higher-intensity rest of the bedrock formed when effects were observed. the supercontinent rifted apart about 200 million years ago to A time history recording of the earth- form what are now the north- quake from the North Anna Nuclear eastern U.S., the Atlantic Ocean, Power Plant approximately 17 km and Europe. The Central Vir- from the epicenter shows a peak ginia seismic zone is far from horizontal ground acceleration of the nearest plate boundaries, 0.27g (Figure 2). The response which are in the center of the spectrum also shows high energy Atlantic Ocean and in the Carib- Figure 3. The fall line (dashed) and terrace content at short periods as com- bean Sea. The seismic zone deposits in the vicinity of the Washington pared to typical west coast earth- is laced with known faults, Monument (source: Collective Works of J. quake spectra. though they are poorly located P. Gould).

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lie directly over the rupture plane. There may have been other lique- faction sites, but the undergrowth in the region is thick and sand depos- its sparse. Several heavy rains associated with Hurricane Irene in the days after the main shock likely washed away any features in the river and creek beds. Slumps and Subsidence. One small slump was found on the bank of the South Anna River very close to the liquefaction features, again likely directly over the rupture plane. What is believed to be earthquake- induced subsidence was found in an abandoned gold mine. Rockfalls. Four rock falls were Figure 4. Aerial image of the epicentral region showing locations of observed found in the epicentral region, two liquefaction sand boils. Also shown are the epicenters of the main shock and along the banks of the South Anna of >M3.0 aftershocks within two days of the main shock (source: GEER). River and two in road cuts. The team determined that the area of Coastal Plain deposits include deposition of relatively fine grained rockfalls extended from just north Cretaceous sediments, Pleistocene alluvium in river channels. of Harper’s Ferry on the north, to Terrace deposits, and river depos- the Virginia/ border The epicentral area is drained by ited alluvium of relatively recent on the west, and to about 10 miles South Anna River and its major, sec- origin. The Cretaceous sediments, north of the North Carolina border, ondary, and tertiary tributaries. Allu- known as the Potomac formation, along the Blue Ridge Parkway, on vium (unconsolidated clay, silt, sand, were deposited in relatively shallow the southwest. They were not able and gravel of Tertiary to Quaternary seas on the sloping bedrock sur- to determine the eastern limit. The age) appears along portions of these face by streams flowing eastward determined limits are shown in streams, typically at leeward-side out of the continental interior. These Figure 5. point bars and horseshoe bend cut- sediments are primarily hard clays offs, ranging from a few meters to Details of the geotechnical effects and compact sands, and a succes- tens of meters thick. Topographic of this earthquake will be published sion of river terrace deposits of sideslopes and hilltops are typically in a forthcoming GEER report Pleistocene times overlies them. underlain by saprolite (decomposed (GEER, 2012). While glacial ice did not reach south bedrock chemically weathered in- to the current Washington, D.C., place) beneath soil horizons; saprolite Damage to Structures area, the terrace deposits were can range from a few meters to tens formed by debris carried in streams Most historic engineered structures of meters thick. charged by glacial melt water flow- located in the densely populated corridor along the Atlantic coast ing from the northwest. Climatic Geotechnical Observations changes resulted in wide variations between and Washington, in stream gradients, sediment load, Liquefaction. The soils in Louisa D.C., were not designed against and deposited materials, so the County are largely residual clay, so earthquake loading and, although terrace deposits consist of mixtures it was not expected that liquefaction the anticipated shaking intensities of silty and sandy clays with clean would be pervasive during this event. are moderate compared to more sands and gravel interlayered and However, the GEER team did find seismically active areas in the lensed in a complex pattern. four small liquefaction sand boils at western United States, the density the locations marked in Figure 4. Also and high monetary value of East Over the period of the last five or marked are epicenters of the main Coast structures puts them at con- six thousand years, the sea level shock and major aftershocks and, if siderable risk to costly earthquake has risen 25-30 feet with respect these epicenters define the general damage (Nikolaou, 2004). to land along the coast. This rise location/orientation of the rupture submerged the Potomac and Ana- Louisa County, Virginia. Several plane of the main shock, it can be EERI team members visited Min- costia Rivers and resulted in the inferred that the liquefaction features

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school buildings. One teacher in the high school knew what to do in an earthquake and had his students take cover under their desks; after the shak- ing stopped, he told the students to evacu- ate the classroom/ school. Other teach- ers had their classes attempt to evacuate the building during the earthquake, and there were several minor injuries reported due to falling debris.

When the schools Figure 5. Aerial image showing the areal extent of were evacuated, stu- rock falls (source: GEER). Figure 6. Damage to Louisa Coun- dents left behind their ty High School (photo: R. Green, backpacks, which eral, the town closest to the epicen- two years, re- GEER). included their cell ter, Louisa City, and other areas in pairing the high phones. The students Louisa County three and four days school (Figure 6) in approximately had no access to their backpacks after the earthquake. They observed four years, and maintaining and for four days, and upon returning, minor to moderate damage to un- demobilizing temporary facilities commented on the inconvenience of reinforced masonry homes and amount to $45M, which will exceed being separated from their phones. schools, failure of brick veneer, mi- the available and applicable insur- nor cracking in reinforced masonry ance by approximately $28.7M. Other schools sustained some struc- and reinforced concrete structures, This is based on assumptions made tural damage, according to school and failure of some residential car- regarding the level of applicable district officials, but can be occupied port structures. insurance, which as of October 20 while repairs are being made. had not been fully defined by the The damage estimate for public insurance company (McDonnell, The Louisa County Office of Emer- buildings and equipment in the 2011). The indefinite school closure gency Management had no reported State of Virginia, as of October 20, of Jefferson Elementary has been damage to its facility and was fully was $30,598,300 (McDonnell, accommodated by bringing mobile operational after the earthquake. 2011). Most of this total is due to units to Trevilians Elementary and The Mineral fire station had limited the costs of repairing the following staggering school shifts. Louisa nonstructural damage and cracking schools: in Louisa County, Thomas County High School will share a in CMU walls, but the damage did Jefferson Elementary ($9.5M) and middle school building until mid- not hamper response activities. Louisa County High School (18.7M), January, at which time a mobile high and in Spotsylvania County, Ger- school will be established on site and The Louisa City water tower, across manna Community College ($1.1M) schedules will return to normal. from the County Court House, and Mary Washington University looked like it had been there at ($689,550). For Louisa County, the The fire alarms at the high school least 50 years, but the anchor bolts damage estimate for total residen- were activated during the earth- showed no movement or stretching. tial damage as of October 20 was quake, apparently because the fire There was no damage to the Court $13,730,000 (McDonnell, 2011). alarm was triggered when the sprin- House, to the historic jail next to the kler system lost pressure due to a Court House, or to the Confederate The cost of repairing Jefferson break in one of the sprinkler pipes. monument in front. Elementary represents 70.9% of EERI team members were told that the estimated $13.4M replacement the schools did not have specific Two historic unreinforced masonry cost, so it is planned to be rebuilt. earthquake response procedures, buildings in the area were moder- Total costs of rebuilding the ele- but rather used the typical fire/tor- ately damaged. The Gilboa Chris- mentary school in approximately nado drill procedures in evacuating tian Church, built in Mineral in 1832,

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quake. Operated by Dominion Power, the plant had gone on auto- matic shutdown immediately after the quake, which triggered back-up power generation. The plant had been designed for a Design Basis Earthquake (Safe Shutdown Earth- quake [SSE]) of 0.12g, but the ground motion was recorded at 0.27g, a little more than twice the SSE. Although the SSE was not intended to be exceeded, the ro- bustness in the seismic design resisted major damage, and North Anna is now back online following review by the owners and the Nuclear Regulatory Commission (NRC).

The team examined several large water tanks, some of the noncriti- cal buildings, the main service building, and the turbine building. Figure 7. Damage to the historic Gilboa Christian Church. Some of the CMU walls in one of the noncritical buildings showed had considerable architectural and as inspectors on loan from jurisdic- hairline diagonal cracks. The tur- some structural damage. As shown tions around Virginia. The inspections bine building is a tall, steel space- in Figure 7, the outer wythe of a were conducted because the county frame structure, and the crane was brick wall collapsed where there needed an estimate of the total cost being tested while we were there. was no apparent connection be- of damages in order to determine The crane appeared to be working tween the wythes of the wall. A por- whether it was eligible to apply for aid fine, which implied very little resid- tion of a gable wall collapsed that from the Commonwealth of Virginia ual displacement of the crane rails. did not appear to be well anchored and the federal government. As such, There was almost no evidence that to the roof diaphragm. A section of the inspections focused on assessing the big water tanks moved relative brick veneer also failed where ties costs (see Figure 9), not on restricting between the brick and backup wall access to dangerous buildings. No consisted of 16d nails driven into damaged building was tagged. straight sheathing and then encased in the brick mortar joint. Approxi- North Anna Nuclear Power Plant. GEER and EERI team members mately 20% of the vertical standing visited the North Anna Nuclear Power tombstones in the Gilboa Church Plant (NPP) a week after the earth- cemetery were thrown over.

The Cuckoo House, a Federal style house in the small village of Cuckoo, near Mineral, was built in 1819 and was listed on the National Register of Historic Places in 1994. The unreinforced masonry build- ing had considerable architectural and some structural damage, with partial collapse of some walls and both tall chimneys (Figure 8). Figure 9. Damage assessment Post-event building inspections form used by Louisa County build- were conducted by approximately Figure 8. Partial collapse of a gable ing inspectors after the earthquake 12 inspectors that included Louisa wall and two chimneys at the Cuck- (source: Scott Keim, Louisa County County building inspectors as well oo House outside Mineral. Fire & EMS Chief).

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Figure 10. 117-ton steel casks for dry storage of spent fuel rods (photos: Dominion Power).

to the foundation, though they were made public. Memorial, with a localized high not tied down; however, it was clear point at the east end of the Reflect- that 27 massive steel storage casks The . In the ing Pool (elevations are referenced for spent fuel rods slid around on 220 years since Pierre L’Enfant first to Mean Sea Level). Figure 13 their concrete slab as much 4.5 envisioned the National Mall as our presents a generalized geologic inches (Figure 10). nation’s “Grand Avenue,” the land has section. For the construction of the been used for a multitude of purposes, western half of the Mall, up to 30 ft. Dominion Power had two accelero- such as military training and railroads, of fill was placed, and most of the graphs that recorded time histories, before it was developed into the se- monuments there are founded on one on the mat foundation of the rene, tree-lined home of museums deep piles. nuclear reactor (shown in Figures and monuments that it is today. The 11 and 2) and one on an elevated Washington Monument stands at the The Washington Monument was operating deck. Also present were center of the mall (Figure 12). one of the earliest structures built multiple spectrum recorders, which on the mall. Construction began in record ordinates at 12 frequencies. Background: The mall is located with- 1848 with private funds raised by Dominion is having the spectrum in the coastal plain that consists of a subscription. The monument foun- recorders analyzed, and then will broad belt of flat sediments over bed- dations were established at approxi- turn the data over to the NRC, at rock. The top of the bedrock along the mately +15 ft of elevation atop the which point the information will be National Mall ranges from about -220 terrace sand and clay deposits. ft. in elevation at When funds ran out in 1856, work the Capitol to -20 to was stopped with the monument at -40 ft. in elevation a height of +152 ft. west of the Lincoln

Figure 11. Acceleration response spectrum for ground motion recorded at the North Anna Nuclear Power Plant Figure 12. Washington Monument (photo: Department of (adapted from Dominion Power, 2011). Defense, 2003).

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Figure 14. Completed buttresses in 1879 (source: Library of Congress, 1880). Figure 13. Geologic section along the Mall, looking north (modified from Christie, 2002; original section in Collective Works of J. P. Gould). the honor of setting the 3,300-pound capstone and securing the alumi- Congress was repeatedly ap- slope of the walls changes. Coinci- num apex to the copper rod that proached for funding, but the Civil dently, an earthquake that was felt in passed through the capstone War intervened. Construction was the D.C. area hit the City (Torres, 1984). not resumed until the late 1870s, metropolitan area a day later, on when funding was forthcoming from August 10, 1884 (Nikolaou, 2004; Total settlements since the begin- Congress. At that time, concerns Tuttle & Seeber, 1989). The intensity ning of underpinning are about 7 were raised about the ability of the at the epicentral region was VII, and inches. However, more than 60% spread foundations bearing on these the estimated local magnitude was of this settlement occurred during soils to carry the load of a masonry 5.5 (USGS, 2009) . No damage to the underpinning and the second phase structure in excess of +500 ft. monument was reported. of construction, as the monument Thomas Lincoln Casey, an experi- was built up from 152 ft. to 555 ft. in enced lieutenant colonel from the Work began on the pyramidion in height. Contributing factors to the U.S. Army Corps of Engineers, de- September 1884, and on the after- settlement that occurred after com- signed a scheme to underpin the noon of December 6th, Casey had pletion of the second phase include foundations. Buttresses were add- ed to provide load transfer to the underpinning, with excavations ex- tending to approximately +3 ft. of elevation, which was the ground- water level at that time (Figure 14). The new foundations bear on the deeper, coarser grained terrace de- posits stratum (Figure 15) and have generally performed satisfactorily.

The last piece of marble was placed on August 9, 1884, com- pleting the shaft to 500 feet, which made it the tallest structure in the world.

It remained to construct the pyra- Perspective view at the base of the Washington Monument (1931) midion — the uppermost 55 feet of Figure 15. (modified from Torres, 1984). the monument, beginning where the

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Figure 17. Crack in the Washing- ton Monument (photo: , 2011b). Figure 16. Inspectors from WJE conducting an exterior inspection (photo: the post-earthquake damage as- National Park Service, 2011b). sessment revealed: • Cracking and spalling of the exte- secondary compression, site re- though it is difficult to differentiate rior marble and underlying stone grading, construction activity, and the arrival of the surface waves, a few masonry elements; nearby dewatering. Settlement seconds after S wave arrival does monitoring in recent years has re- correspond to the point at which the • Loss of joint mortar; vealed minimal settlement, indicat- majority of the debris falls from the • Debonding of cementitious patch- ing that the monument is stable and ceiling. It is also clear that the monu- ing material used throughout the that the underpinning operation was ment continues to move more than monument; successful (Christie, 2008). three minutes after the shaking be- • Debris consisting of mortar, stone/ gan. Late-arriving surface waves and paint chips, and stone pieces sur- Damage: Video from a camera reflected/scattered seismic waves rounding the base of the monu- installed at the 500 feet level of the account for the long shaking duration. ment and covering the interior monument clearly shows shaking stairs and observation deck; that can be attributed to the arrival An official interior and exterior dam- • Damage to the elevator system of various seismic waves. To see age assessment was conducted by (elevator could only ascend 250 ft the video, visit http://www.nps.gov/ the National Park Service, including of the 555 ft tall structure); wamo/photosmultimedia/videos.htm a climbing team to “rappel all four (National Park Service, 2011a). At faces of the Washington Monument • Additional damage due to wind the distance of the monument from to perform a close range survey of and water entering through cracks the earthquake epicenter (135 km), the exterior surfaces” (Smith, 2011) during Hurricane Irene, which hit the P wave arrives about 24 sec- (Figure 16). The National Park Ser- D.C. on August 27th, 2011; onds after the earthquake rupture vice engaged two outside engineering • Partially dislodged masonry begins. The S wave should arrive firms (WJE Associates and Tipping blocks. about 17.5 seconds later, and the Mar Associates) to assist with the The most significant damage was video clearly shows an increase in investigation. Although the external found in the pyramidion at the top of shaking about 17-18 seconds after inspection was officially completed in the structure, where a 4-foot long, onset of the P wave. Debris begins early October 2011, the Washington 1-inch wide crack was observed to fall from the ceiling less than two Monument currently remains closed (Figure 17). Engineers and inspec- seconds after the S wave arrival. to the public (Ruane, 2011a). tors were assisted in the damage Theoretically, the Raleigh and Love assessment by a study of the Wash- surface waves should arrive about Initial published findings (WJE, 2011; ington Monument that was com- 3-4 seconds after the S wave; al- Sullivan, 2011; Ruane, 2011b) of pleted in 1999 prior to a rehabilita-

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◄ Figure 18. ▲ Figure 19. Damaged chimneys of Wall cracking the Smithsonian Castle. around Castle windows; this the Castle. There was considerable window moved shear cracking throughout the build- outward about ing, especially around windows and one-fourth major corners (Figure 18). The large inch.) chimneys cracked to the point that they had to be wrapped in plywood and restrained (Figure 19). tion effort (Ruane, 2011b). The org/2011-08-23-virginia/category/ There were also reports of damage information gathered during that geotechnical/. at a Smithsonian warehouse com- study was used for comparison . Based on plex approximately six miles from with current damage. Final deter- initial reports of very limited damage, the Mall in Maryland. There, five mination was that the monument the EERI team did not conduct gen- warehouse buildings (called pods) was structurally sound, but will not eral reconnaissance of structural dam- store thousands of historical arti- be reopened to the public until age outside the epicentral region; how- facts from around the world. They further notice. ever, the GEER and EERI teams were are typical warehouse buildings of With the damage assessment invited by the secretary of the Smith- concrete-framed construction and now complete, the National Park sonian Institution (Wayne Clough, a infilled walls with double-T concrete Service and other agencies will geotechnical engineer and former roofs. The interior storage area consider the repairs that must be EERI member) to document damage consists of three floors of steel made and the implications of this in two of the Smithsonian facilities: constructed as standard mezzanine event on planning and emergency the administration building in D.C. and floors that carry the loads to steel preparedness procedures. a large storage facility in suburban columns and down to the building Maryland. foundations. The steel storage area The detailed special report to is independent of the warehouse EERI on the Washington Monu- The Smithsonian Institute’s structures structure, except they share the ment (Nikolaou et al., 2011) that is represent a complex mix of structure same foundation. excerpted in this section is avail- types and uses. The Institution’s ad- able on EERI’s clearinghouse site ministration building is located on the In one pod there was damage in a at http://www.eqclearinghouse. Mall; it was built in the mid-1800s of stair well that consisted of concrete stone and masonry and is known as construction that transferred to

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Figure 20. Concrete stairwell. Notice infilled wall crack Figure 21. Stairwell concrete column failure at first mez- (blue tape) at framing beam in warehouse wall across zanine floor level. from stairs.

steel mezzanine construction once placement could have been as much Additionally, two people who later one got to each floor level (see as three inches. became team members were in Figures 20 and 21). downtown Washington at the time Social Impacts of the earthquake and were able to In the steel artifact storage area of observe the resulting evacuation, one pod there was evidence of con- Perhaps the most significant social communication, and transportation siderable seismic load (Figure 22). impacts associated with this earth- problems. Team members from the Two approximately 1-inch anchor quake were those in major metropoli- Disaster Research Center (DRC) bolts completely sheared and the tan areas, particularly Washington, also interviewed local and national tension cross brace yielded. Not only D.C., and parts of suburban Maryland government officials and private citi- did that steel brace yield in tension, and Virginia. These areas are unpre- zens in Mineral and Culpeper, Vir- but one brace actually ruptured. pared to deal with even a moderate ginia, as well as in Washington, D.C. earthquake, particularly with respect The building and the independent to evacuation, communications, and Earthquake Preparedness. As steel-framed storage structure transportation. Insights on these is- with other communities in moder- moved differentially during the earth- sues were gained by reconnaissance ate seismic risk zones on the East quake, as evidenced by damaged team members primarily through inter- Coast, the inhabitants of the towns insulation seen in vertical pipes views with emergency management and cities affected by this earth- (Figure 23). The differential dis- and transportation officials in the area. quake have little earthquake

Figure 22. Base floor of artifact storage area showing sheered steel framing support anchorage and brace Figure 23. Battered insulation of vertical pipe through yielding (flaked off paint) at plate connection. mezzanine floors.

10 EERI Special Earthquake Report — December 2011 awareness and no preparedness uments on the National Mall, the their quest for information and di- planning. The local emergency National Cathedral, and City Hall in rection, as exemplified by the ex- management agencies in Washing- New York. change of information in crowds on ton, D.C., and surrounding suburbs Those that left their buildings during the streets and, later, on crowded have capable, professional staffs the actual shaking violated the most subway platforms. If the earthquake and relatively good resources, this basic rule of earthquake response had been a major disaster, the tech- being one of the wealthiest areas in in high seismic risk states like Cali- nological problems that emerged the country, but the organizations fornia, but at all the places the team would have led to far greater dis- have given little or no attention to collected information — from Mineral, ruption. earthquake preparedness. Building Virginia, to Washington, D.C., — a security personnel have no training The surge in cell phone use in the great majority of people said they about earthquakes, and schools metropolitan area and elsewhere thought it was something else which give scant attention to the earth- brought about a two-hour period with they are more familiar — a ter- quake risk, focusing instead on fires, during which customers could not rorist attack, transportation accident, as reflected in their regular fire complete calls, even legitimate 911 or hurricane. Many indicated that they drills, on nuclear incidents, or on calls. The major carriers — AT&T, evacuated their buildings because school invaders. , T-Mobile and Sprint — re- evacuation was part of their fire drills, ported no physical damage to their Neither stu- Building Evacuation. the emergency for which they prac- wireless systems, but their net- dents nor the general public have ticed most. In Mineral, many respon- works were all overloaded. The been instructed on actions to take dents thought it was an incident at the performance of landline networks in case of an earthquake, including North Anna Nuclear Power Plant, and varied across the area. Evacuees the generally accepted guidance to they rushed around the neighborhood that had gotten through to someone drop, cover, and hold on while in- to check on older residents. shared the information messages side a building. Instead, emergency In Washington, people remained ad- they had with others. Emergency planning is directed at potential ter- jacent to their buildings, which ex- services organizations relied on rorist attacks, and the public displays posed them to possible collapsing radio and satellites to communicate. much greater awareness of that walls and parapets; those who con- Some employers sent emails to than the earthquake threat. Many gregated in the streets blocked traffic. their staffs, while others used loud- building occupants decided to evac- A smaller number of evacuees went speakers in the streets to commu- uate immediately when the shaking to the open areas of small parks and nicate instructions and information began — hardly surprising in light squares, which in many cases were to their employees. The speed of of their awareness of terrorism — still close to potential building hazards. re-establishing cell networks varied though some residents who had Some patrons in outdoor restaurants among providers. lived in California reported that they next to large buildings were observed sensed that the shaking was caused nonchalantly eating during and after Transportation. After the earth- by an earthquake rather than a ter- the shaking. quake, flights were delayed or sus- rorist strike and therefore stayed in pended by the Federal Aviation In a disaster, peo- place. Communication. Administration at airports in New ple use both traditional and nontradi- One of the enduring images of re- York, Newark, and Washington, tional ways to get critical information sponse to the earthquake, captured D.C., so the facilities could be that will help them decide how to by television and newspapers from inspected. Some trains and sub- cope. The large crowds outside build- around the country, were the tens of ways were delayed because tracks ings were observed milling — moving thousands of people who evacuated and bridges had to be inspected for about and talking with acquaintances, office and apartment buildings up damage. Travelers on streets and coworkers, and strangers on the street. and down the East Coast, most no- highways and subways also faced Others sought news and information tably in downtown Washington and challenges. The surge of people from the radio and their cell phones. in New York City. Many moved out using the highways and express- People wanted to know exactly what of buildings on their own initiative, ways to get home exacerbated de- had happened, whether or not they or because they were prompted by lays in a region known for its traffic should return to work or go home, the co-workers and friends, while others problems even in normal times. condition of the transportation system were told to do so by authorities. A surge in ridership also slowed and roads, and, most importantly, the Elevators were a favored means of service on parts of the Metro sys- status of family members and friends. evacuation unless people were tem. Many subway entrances and directed to use stairs. Major land- The demands placed on communi- platforms became dangerously marks were evacuated, including cation technology exceeded its cap- overcrowded. the , the Capitol, mon- acity, forcing people to innovate in

11 EERI Special Earthquake Report — December 2011

In the aftermath of the quake, historic and highly symbolic struc- ning for hazards that communities questions have arisen about the tures in Washington, D.C., that are in the region are most familiar with, provision of sound and timely undergoing extensive inspections and such as hurricanes, terrorism, and information by authorities. Trans- repairs. Both the Washington National fire. Many principles apply to pre- portation agencies tried their best Cathedral and the Washington Monu- paredness for all hazards; some to transmit news through radio ment have been closed to visitors. principles differ, but good public announcements and social media, The National Park Service, which education can provide the critical but many people have complained manages the Washington Monument, information in every case. For ex- about a lack of useful intelligence. has announced that the structure will ample, guidelines for building evac- Communications difficulties are be closed indefinitely, and repairs on uations could incorporate earth- common to all crises — indeed the National Cathedral are expected quake information along with that define them to some extent — and to take years. for fire. Plans for inspecting hurri- only advanced planning and coor- Questions have arisen regarding the cane damage could be expanded dination can ameliorate the chal- direction that can be taken in protect- to include the particulars for earth- lenges. The Metropolitan Washing- ing historic buildings from future earth- quake-induced damage. Public and ton Council of Governments, a quakes, and how much can be done private decision makers should rec- region-wide entity, is now working while still maintaining their historic ognize that improving communica- on a strategy to improve coordina- integrity. These questions are familiar tions, such as assuring power to tion of transportation information. to those in any active seismic zone cell towers and prioritizing 911 calls, will be of significant benefit in all Recovery who have dealt with historic buildings before or after quakes, but new to future crises, including earthquakes. Soon after the earthquake, most on the East Coast. National EQECAT, the catastrophe risk mod- Cathedral officials interviewed shortly Acknowledgments eling firm, estimated losses on the after the quake had no plans for re- The authors greatly appreciate infor- East Coast at $200-$300 million, habilitating the structure so that it mation provided by George Roarty, with less than $100 million of that might better withstand future seismic director of the Recovery and Mitiga- insured (Washington Post, 2011). events. There is a need for strong- tion Division of the Virginia Depart- These early estimates will undoubt- motion accelerometers to be installed ment of Emergency Management; edly be refined when more damage in important structures to provide rec- Matthew Heller, geologic mapping data becomes available. More re- ords of ground motions. This would manager at the Virginia Department cent inspections of some structures help improve our understanding of of Mines, Minerals, and Energy; have determined that they were the type of earthquakes that occur on and James W. Dewey of the Earth- damaged more than originally the East Coast and the effects that quake Hazards Program at the U.S. thought. the unique geology in this area could Geological Survey office in Golden, have. Colorado. For the most part, in undamaged evacuated buildings in Washington, An Alternative Future This report was edited by Sarah K. D.C., activities resumed either Nathe, EERI’s Learning from Earth- hours after the earthquake or the The day after the earthquake, two of quakes insert editor, and formatted next day. Communications net- the emergency management agen- by Eloise Gilland, EERI Publications works throughout the East Coast cies in the Washington, D.C., area — Manager, who also did supplemental rebounded a few hours after the the District of Columbia Emergency editing and composed the section earthquake, and disruptions to Management Agency and the Mont- on school damage repair under the such transportation systems as air- gomery County Office of Emergency “Louisa County, Virginia” subhead- ports and subways lasted only until Management and Homeland Secu- ing, based on information provided safety inspections were completed rity — posted guidelines for earth- by Roarty. on the day of the event. quake safety on their websites for the first time. Such simple acts suggest Some school systems have had a that improved earthquake prepared- References longer road to recovery. For exam- ness is possible in the region. How- Christie, D.W. (2002). “The Geol- ple, schools were closed in parts ever, this requires increased earth- ogy, History, and Foundations of of the Washington, D.C., area and quake awareness among policy Washington DC’s Monumental in Louisa County for an extended makers and practitioners, and pub- Core,” American Civil Engineer- period, including the two damaged lic education initiatives. ing History, The Pioneering Years, schools in Mineral, Virginia (see Proc. 4th National Congress on page 4). Also on a slow recovery A first step would be to integrate Civil Engineering History and trajectory are some of the damaged earthquakes into preparedness plan- Heritage, ASCE.

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Christie, D.W. (2008). “Foundations with attachments requesting major Torres, Louis (1984). To the immor- for Memorials and Monuments disaster declaration authorization, tal name and memory of George on the National Mall,” Proc. 6th Commonwealth of Virginia, Office Washington, the United States International Conference on Case of the Governor, October 21. Army Corps of Engineers and Histories in Geotechnical Engi- Mittelbach, M., & M. Crewdson the construction of the Wash- neering, Arlington, VA, August (1998). Wild New York: A Guide to ington Monument. Washington, 11-16. the Wildlife, Wild Places, and Natu- D.C.: Historical Division, Office of ral Phenomena of New York City, Administrative Services, Office of Department of Defense, (2003). Crown Publishing Group. the Chief of Engineers. photo by Tech. Sgt. Andy Dun- Tuttle, M. P. & L. Seeber (1989). away, U.S. Air Force, Sept. 26: National Park Service, (2011a). 500 http://www.news.navy.mil/ “Earthquake-Induced Liquefac- ft level Video 1st View, 500 ft level tion in the Northeastern United view_single.asp?id=9756, photo Video 2nd View, 500 ft level Video 030926-F-2828D-080 States: Historical Effects and 3rd View. http://www.nps.gov/ Geological Constraints,” Annals wamo/photosmultimedia/videos.htm Dominion Power, (2011). “Over- of NYC Academy of Sciences, K. view of 08/23/11 Earthquake H. Jacob & C. J. Turkstra, eds., National Park Service, (2011b). 558: 196-207. Response and Restart Readiness Photo Gallery, Washington Monu- Demonstration Plan.” Presenta- ment Earthquake Damage. http:// tion to the Nuclear Regulatory U.S. Geological Survey, (2009). www.nps.gov/wamo/photosmulti- Historic Earthquakes, http:// Commission on September 8, media/photogallery.htm 2011. earthquake.usgs.gov/ Nikolaou, S. (2004). “Effect of Local earthquakes/states/ Ellsworth, W.L., et al., in prepara- Geology on Ground Motion in events/1884_08_10.php. tion. “The Mw 5.8 Virginia earth- New York,” Invited Paper & Spe- quake of August 23, 2011: a high- cial Presentation, 5th International U.S. Geological Survey, (2011a). stress drop event in a critically Conference on Case Studies in “Magnitude 5.8 — Virginia: stressed crust,” Presented at Geotechnical Engineering, New Summary,” http://earthquake. the 83rd annual meeting of the York City, April 16, 14 p. usgs.gov/earthquakes/eqinthe- Eastern Section of the SSA, news/2011/se082311a/#summary October, 2011. To be published in Nikolaou, S., C. Z. Beyzaei, D. W. Seismological Research Letters Christie, & H. S. Lacy (2011). “The U.S. Geological Survey, (2011b), in late 2011. Washington Monument: Geology, “Did You Feel It? M5.8 - Virginia,” Foundations, & Earthquake His- http://earthquake.usgs.gov/earth- GEER (Geotechnical Extreme tory: Special Report to EERI on the Events Reconnaissance) Team quakes/dyfi/events/se/082311a/ 2011 Virginia Earthquake,” Mueser us/index.html (2012). Geotechnical Reconnais- Rutledge Consulting Engineers, sance of the 2011 Central Virginia New York City, http://www.eqclear- Washington Post (2011). “Region Earthquake: Report of the Nation- inghouse.org/2011-08-23-virginia/ Tallies Earthquake Damage, al Science Foundation-Sponsored category/geotechnical/ Mostly Uninsured,” August 24. GEER Team. J. R. Martin, (edi- Ruane, M. (2011a). “Washington WJE (Wiss, Janney, Elstner Associ- tor). Contributing authors: C. Ben- ates), Inc. (2011). “Washington son, M. Chapman, M. Eddy, R. Monument closed indefinitely.”, Sept. 26. Monument Post-Earthquake Green, A. Kammerer, S. Lasley, Survey and Condition Assess- C. Lazarte, S. Nikolaou, B. Tanyu, Ruane, M. (2011b). “Washington ment.” and M. Tuttle. Forthcoming. Monument external earthquake Gould, J. P. (1953-1998). “Collective inspection complete.” The Wash- Works on the Geology and Foun- ington Post, Oct. 5. dations of Washington, D.C.,” Smith, M. (2011). “Climbers Rappel Mueser Rutledge Consulting Washington Monument to Assess Engineers files. Damage.” WAMU 88.5 American Library of Congress (1880). Pho- University Radio. Sept. 26. tograph USZ62-30612, January, Sullivan, P. (2011). “Washington Mon- http://www.loc.gov/pictures/item/ ument cracks indicate earthquake cph15109/ damage (Photos).” The Washington McDonnell, Robert (2011). Letter Post. Aug. 25, 2011. to the President through FEMA

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