Review ArticleCan Repetitive Small Magnitude-Induced Seismic EventsActually Cause Damage

Oliver-DenzilSTaylor 1AlannaPLester1TheodoreALeeIII2andMihanHMcKenna1

1US Army Corps of Engineers Engineer Research and Development Center Geotechnical and Structures Laboratory VicksburgMS 39180 USA2US Army Corps of Engineers Engineer Research and Development Center USACE Reachback Operations Center MobileAL 36602 USA

Correspondence should be addressed to Oliver-Denzil S Taylor oliverdtaylorusacearmymil

Received 12 January 2018 Accepted 10 April 2018 Published 8 May 2018

Academic Editor Tiago Miguel Ferreira

Copyright copy 2018 Oliver-Denzil S Taylor et al is is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Geoengineering activities such as reservoir impoundment mining wastewater injection geothermal systems and CO2 capturehave been linked directly to induced seismicity With the industrial boom in natural shale gas production regions previouslyaseismic areas have seen an exponential growth in the frequency of small magnitude events with multiple events observed in closeproximity within a 24-hour time period While the overwhelming majority of induced seismic research has focused on thecausality the potential risk posed to critical federal infrastructure has escaped scrutinyis proposes the question ldquoCan repetitivesmall magnitude-induced seismic events actually cause damagerdquo A review of the potential risk is presented herein concludingthat a simplistic definitive statement of whether single or multiple small magnitude-induced seismic events do or do not causedamage to critical infrastructure cannot be justified and warrants additional study However recent observations and researchsuggest the likelihood that these geoengineering-induced events can and do cause detrimental degradation of the subsurface(damaging the overlying structure) is not insignificant

1 Introduction

Recent induced seismic research has shown that the currentstandard of practice for risk assessment for infrastructure isnot applicable for the UHP-induced seismic hazard in his-torically aseismic continental regions [1 2] but is criticallyimportant for understanding the immediate impact potentialto USACE-owned dams and levees throughout the Centraland southwest central United States (CeUS) Engineeringeconomic social and political decision-making matricesmust therefore include the questions of ldquoWhat is the largestexpected induced seismic eventrdquo and ldquoWhat is the probabilityof an induced seismic event generating a potentially damaginggroundmotionrdquoe answers to these questions are currentlythe focus of emerging research [1ndash4]

Intraplate regions are primed to be susceptible to in-duced earthquakes as the geological stress states are alreadyat critical stress conditions the geological structure is ina quasistatic equilibrium state [3 5ndash7] Recent advances in

fluid-based geoengineering activities hydraulic fracturingenhanced recovery technology population growth andworldwide energy consumption rates are suspected ofcontributing to the exponential increase in seismic activitywithin these historically aseismic regions by altering deeplithology effective stress states which result in subsurfaceshear failure [1ndash3 5 6 8ndash20] Seismologists and earthquakeengineers have recently issued concerns about fluid-basedgeoengineering activities being the genesis of moderateinduced seismicity [1 2 4 19ndash21] yet the topic of damagepotential of geoengineering-induced seismicity remainsrelatively unexplored

2 Geoengineering-Induced Seismicity

e exponential rise in induced seismicity in the CeUS since2008 is correlated with an increase in Modified MercalliIntensities (MMI) from small relatively shallow events[1 2 5 22] Common geophysical practice adheres to the

HindawiAdvances in Civil EngineeringVolume 2018 Article ID 2056123 5 pageshttpsdoiorg10115520182056123

premise that seismicity below M50 is not significant forgenerating damaging ground motions and thus is notconsidered a substantial hazard to critical infrastructure[1 2 4] Increased MMI combined with encroaching spa-tiotemporal proximity to critical infrastructure begs thequestion ldquoCould future small magnitude-induced eventsaffect federal flood control structures and critical in-frastructurerdquo is is particularly important to the aginginfrastructure within the United States where some criticalstructures are beyond design life spans andor designedwithout any seismic considerations [23]

is recent rise in seismicity within the CeUS appears tobe different from what has been historically observed asthese events are more shallow (typically between 2 and 5 kmin depth as opposed to 10+ km for historically tectonicevents) are smaller in magnitude are persistent and occurin previously essentially aseismic areas [3 24ndash27] It must benoted that the spatial location and average depth of recentevents are loosely constrained due to instrument coverageand limitations within location algorithms and some re-gions for example Oklahoma have default depths of 5 kmfor shallow events for events whose location accuracies areuncertain However the recent events reported are pre-dominately occurring within the upper 5 km of the crust[24ndash27] More important is the temporal frequency of theseevents Recent research on the spatial-temporal behavior ofgeoengineering-induced seismicity shows that these eventscan be highly concentrated for example a single region inArkansas exhibited 65 events per km2 at a rate of about 146events per year between 2004 and 2013 [1 2] Some regionsin the CeUS average over two events daily

3 Damage Potential ofGeoengineering-Induced Seismicity

Small magnitude (between M3 and M5) shallow (2ndash5 km)geoengineering-induced seismic events have demonstrateddamage to many types of structures Nowhere is this moreapparent than in aseismic intraplate regions wherein damageis observed from both single and repeated small shallowevents A series of shallow events in Alberta Canada (largestevent M40) caused some minor building damage [19 28]Residential damage has been observed within the CentralUnited States for example the 2012 Timpson Texas se-quence (largest event ofMW-RMT 48) [29] and the 2013 AzelTexas sequence (largest event M37) [30] In CherokeeOklahoma there were several events on February 5 2015(largest event of M42) wherein interior walls were damagedin the Alfalfa County Courthouse [30ndash32] In November2014 an M49 event occurred in the vicinity of Milan KSwith damage to the Harper County courthouse as well as tosurrounding churches and residences events continuedthrough the spring of 2015 wherein new cracks generatedand existing building cracks enlarged [9 33ndash35] On May 22015 an M42 event occurred in Michigan with residentialand commercial damage for example cracks in walls[36 37] is by no means an all-inclusive list however it istypical of the seemingly inconsequential damage docu-mented from induced seismicity Could future small

magnitude-induced events affect larger and heavier struc-tures Quinn and Taylor [38] showed fatigue failure po-tential from induced strains in earthen structures subjectedto minor ground accelerations while under normal toslightly elevated service load and not necessarily limited tosudden catastrophic failure from a single large event Moreimportantly these damage reports indicate potentially moreproblematic hazards (1) repetitive loading and (2) subsurfacefatigue

4 Single-Event Failure versusMultievent Fatigue

e repetitious nature of these events may generate cumu-lative damage effects or fatigue well in excess of the initialstructural design Moreover these seemingly inconsequentialdynamic loading scenarios are often dismissed as poten-tially damaging in favor of a single isolated event that is ifa structure can withstand a much larger extreme event thena minor event poses no significant threat is would bea safe assumption provided that the occurrence frequency ofthe smaller events was not significant For example in RhodeIsland there have been numerous cases wherein vibrationscaused by pile driving have resulted in detrimental settle-ment of adjacent structures (similar to the damage corre-lated with induced seismicity) leading to the demolition ofsome historic structures [39] ese vibrations were causedby impact hammers operating at low strike frequencieswherein each pile strike generated seismic velocities wellbelow construction thresholds for even the most sensitivestructures erefore the question of damage potentialbecomes a source scaling issue

Dynamic responses decay as a function of distance froman energy source Finite seismic sources for example singleinduced events in a bounded elastic media have a geometricamplitude decay of

A2 A1r1

r21113888 1113889

n

(1)

where r1 is the radial distance from the source to a knownamplitude A1 r2 is the radial distance to an unknownamplitude A2 and n is the exponent of decay depending onthe seismic wave type Small magnitude events M5minus ata shallow depth can yield surface ground motions well inexcess of much larger M7+ tectonic earthquakes simply dueto a significantly reduced r2 us simply negating damagepotential based strictly on magnitude determinations is bothmathematically and physically incorrect New ground mo-tion prediction equations are required for these events[4 40] Induced events have much shorter duration andhigher frequency contents [19 29] For structures of lownatural frequencies single high-frequency peak accelerationwould have little effect to the physical structure [41]erefore it is unlikely that an induced event would causesignificant damage to a large nonearthen structure How-ever if we associate these induced events as an impulse forcethat is single-cycle large amplitude loading the primarydriver for damage potential is not the cyclic or frequency

2 Advances in Civil Engineering

eects to the physical structure rather the damage potentialis the subsurface yield that can cause detrimental settlementand structural damage

Engineers and geophysicists often consider the crustalpore space regardless of airwater make-up to be initiallystatic is assumption is valid for tectonic cases whereearthquakes are years to decades apart In regions of fre-quent induced seismicity where events are hours to daysapart pore pressures are not necessarily static at the onset ofsubsequent induced events [1 2] In terms of ground re-sponse for liqueable cohesionless soils excess pore pressuregeneration is relatively independent of loading frequencywith dissipation being a function of permeability [39 42]Moreover excess pore pressure ratios do not need to achieveunity to cause signicant strains within a cohesionlesscontinuum strains as low as 03 can indicate the onset ofuncontrolled degradation within the subsurface [39] isdegradation or strength reduction may cause dierentialsettlement beneath a structure leading to foundation damageor failures even though the physical structure would benegligibly aected by the induced seismic waveform Forexample a loose liqueable nonplastic silt has a cyclic re-sistance ratio CRR of 0187 at the onset of signicantstraining Figure 1 (a M75 tectonic event corresponds to 15equivalent loading cycles [43]) the CRR increases to ap-proximately 0294 for a single cycle equivalentus based onSeed and Idriss [44] and Seed et al [45] the smallermagnitude-induced event would have to yield approximately15 times increase in peak acceleration to initiate signicantsubsurface straining For tectonic events such acceleration isnot achieved with a decrease in earthquake magnitudeHowever for induced seismicity (1) illustrates that such anincrease in acceleration with a decrease in earthquake mag-nitude is possible due to the shallow hypocenter

A typical earthen structure may have a minimumthreshold equivalent acceleration of approximately 02 gbefore the onset of straining (damage) is believed to occurtypically referenced as 15 equivalent loading cycleserefore in the case of loose liqueable nonplastic silt lensa single-cycle equivalent event that is induced seismicevent would require an acceleration of approximately 030 gto have the same damage potential Peak accelerations inexcess of this example have been observed in induced eventsfor example mbLg 41 Timpson Texas with peak accelera-tions of up to 062 g [29] If the induced seismic eventequivalent loading cycles increase to four then the requiredacceleration to achieve the same 02 g threshold remainsrelatively unchanged at 027 g thus justifying a single in-duced event as impulse load Repetitive induced events canthen be treated as a low frequency loading equivalents witha sinusoidal maximum equivalent to the impulse

Eects on smaller structures from high frequencies (bothtemporal and spectral) not the amplitude of the accelera-tion can be observed at a signicant distance from theepicenter and would observationally manifest in intensityreports While aftershocks from tectonic events decrease inmagnitude induced seismicity magnitudes remain relativelyconstant for each subsequent event making the impulseload relatively constant with each event [1 2] us it is

misleading to compare tectonic earthquakes and inducedseismicity without accounting explicitly for variance inloading mechanisms In regions of frequent induced seis-micity structures subjected to repetitive impulse loadings donot consider soil fatigue states Such conditions are explicitlyaccounted in for other aspects of civil engineering for ex-ample trac vibration in bridge design in either design orassessment processes and should be included in discussionsof the subsurface damage potential for induced seismicitydue to the risk to the overall stability

ere are unknown eects that may increase the damagepotential from induced seismicity for example the largevertical acceleration component as observed in TimpsonTexas [29] Our understanding of seismic loading is based ontectonic events that manifest as large horizontal groundmotions with minimal inuence from the vertical compo-nent which is often ignored is change in loading di-rection alters the shearing axis and therefore the soilrsquoscapacity to resist the imparted load Further an appliedshear load propagating vertically from the subsurface ismore representative of an extension type loading this is theweakest axis for soil resistance and warrants further study

5 Hazard and Risk

Induced seismic events do not carry the same hazard as largetectonic equivalents In tectonic events the radial extent oflarge ground motions exceeds that of what has been ob-served in shallow induced seismicity erefore the asso-ciative risk to critical infrastructure of a single inducedseismic event would decrease in comparison based on howrisk is calculated [46]

Seismic Risk Seismic Hazard Θ Vulnerability (2)

e Vulnerability of any structure is a function of ex-posure (within the proximity of the seismic event such thatit may potentially be aected) fragility (susceptibility ofthe structure to the ground intensities) and consequence(socioeconomic impact should failure occur) [22] In (2) the

035

03

025

02

015

01

Cycli

c stre

ss ra

tio (C

SR)

CRR = 0294 Nndash0167

R2 = 0907

10 1001Number of equivalent cycles to the onset of uncontrolled

degradation (N)

Figure 1 e cyclic resistance to the onset of uncontrolleddegradation of a loose to medium dense nonplastic Rhode Islandsilt (after 40)

Advances in Civil Engineering 3

Seismic Hazard or probability of exceedance of a specifiedground motion intensity for tectonic events (the PGAPGV spectral content etc) can readily exceed that of in-duced events [1 2] on a per event basis However the closespatial proximity and repetitious nature of induced eventsactually increase the exposure or the chance that an inducedepicenter will occur within sufficient proximity to exceeda threshold acceleration by increasing the probability ofan event occurrence shown in the b-value for inducedevents [1 2]

Quinn and Taylor [38] illustrated that in the case ofearthen dams normal to slight increases in one hazard(eg the impounded water head) can reduce the requiredseismic hazard threshold for exceedance In this scenariothe Seismic Risk would be a joint probability function of theSeismic Hazard and the secondary hazard (eg floodevent) It is then possible that repetitive low magnitude-induced events combined with a secondary hazard result ina higher Seismic Risk or failure potential than a largertectonic event is may yield a situation where thestructural design is insufficient and the probability of oc-currence is greater for the joint-induced seismic-secondaryhazard event despite the structure being designed fora larger single tectonic event

6 Conclusions

e answer to ldquoCan repetitive small magnitude-inducedseismic events actually cause damagerdquo requires a betterunderstanding of the extent of failure modes (classic failureversus soil fatigue) and threshold limits within the seismichazard and vulnerability of structures ill-equipped towithstand seismic loading Further complicating thequantification of the Seismic Hazard for geoengineering-induced events is that the full extent of the hazard is not fullyknown and varies with changes in geoengineering activitieslocations and technologies [2] us making inducedseismic hazard maps and other measures is currently moresubjective than quantitative Furthermore the Vulnerabilityis complicated by the age of the infrastructure for exampledams locks levee and so on For example the US ArmyCorps of Engineers oversees maintains or operates over 700dams 14500 miles of levees and 220 locks [23] Most ofthese are aging facilities in need of constant repair andrehabilitation eleven of these locks are in excess of 100 yearsold [23] Such conditions lower the exceedance thresholdwithin the Seismic Hazard and increase the fragility withinthe Vulnerability thereby generating even greater SeismicRisk for small magnitude events both on single-event andmultiple event bases us a simplistic definitive statementof whether single or multiple small magnitudeinducedseismic events do or do not cause damage to critical in-frastructure cannot be justified on the basis of comparativemagnitudes between induced and tectonic events andwarrants additional study especially in respect to soil fa-tigue However recent observations and research suggest thelikelihood that these geoengineering-induced events can anddo cause detrimental degradation of the subsurface (dam-aging the overlying structure) is not insignificant

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e research was funded through the Assistant Secretary ofthe Army Acquisition Logistics and Technology (ASAALT)Military Engineering Direct Research program AT40ldquoRemote Assessment of Critical Infrastructurerdquo DirectorGeotechnical and Structures Laboratory US Army Engi-neer Research amp Development Center granted permissionto publish this research with unlimited distribution

References

[1] O-D S Taylor A P Lester and T A Lee ldquoHazard andrisk potential of unconventional hydrocarbon development-induced seismicity within the central United Statesrdquo NaturalHazards Review vol 16 no 4 p 04015008 2015

[2] O-D S Taylor A P Lester and T A Lee UnconventionalHydrocarbon Development Hazards within the Central UnitedStates Report 1 Overview and Potential Risk To InfrastructureERDCGSL TR-15ndash26 US Army Engineer Research andDevelopment Center Vicksburg MS USA 2015

[3] A McGarr ldquoMaximum magnitude earthquakes inducedby fluid injectionrdquo Journal of Geophysical Research SolidEarth vol 119 no 2 pp 1008ndash1019 2014

[4] G M Atkinson ldquoGround-motion prediction equation for small-to-moderate events at short hypocentral distances with appli-cation to induced-seismicity hazardsrdquo Bulletin of the Seismo-logical Society of America vol 105 no 2A pp 981ndash992 2015

[5] W L Ellsworth ldquoInjection-induced earthquakesrdquo Sciencevol 341 no 6142 p 1225942 2013

[6] T R Harper ldquoEffective stress history and the potential forseismicity associated with hydraulic fracturing of shalereservoirsrdquo Journal of the Geological Society vol 171 no 4pp 481ndash492 2014

[7] S E Hough L Seeber and J G Armbruster ldquoIntraplatetriggered earthquakes observations and interpretationsrdquoBulletin of the Seismological Society of America vol 93 no 5pp 2212ndash2221 2003

[8] E Brodsky and L Lajoie ldquoAnthropogenic seismicity rates andoperational parameters at the Salton Sea Geothermal FieldrdquoScience vol 341 no 6145 pp 543ndash546 2013

[9] H Davis KWCH12 News Earthquakes Take Toll on HarperCounty Courthouse June 2015 httpwwwkwchcomnewslocal-newsearthquakes-take-toll-on-harper-county-courthouse31183754

[10] C Frohlich C Hayward B Stump and E Potter ldquoeDallas-Fort Worth earthquake sequence October 2008 through May2009rdquo Bulletin of the Seismological Society of America vol 101no 1 pp 327ndash340 2011

[11] C Frohlich ldquoTwo-year survey comparing earthquake activity andinjection-well locations in the Barnett Shale Texasrdquo Proceedingsof the National Academy of Sciences Earth Planetary and At-mospheric Sciences vol 109 no 35 pp 13934ndash13938 2012

[12] C Frohlich and M Brunt ldquoTwo-year survey of earthquakesand injectionproduction wells in the Eagle Ford Shale Texasprior to the Mw48 20 October 2011 earthquakerdquo Earth andPlanetary Science Letters vol 379 pp 56ndash63 2013

[13] S Horton ldquoDisposal of hydrofracking waste fluid by injectioninto subsurface aquifers triggers earthquake warm in Central

4 Advances in Civil Engineering

eects to the physical structure rather the damage potentialis the subsurface yield that can cause detrimental settlementand structural damage

Engineers and geophysicists often consider the crustalpore space regardless of airwater make-up to be initiallystatic is assumption is valid for tectonic cases whereearthquakes are years to decades apart In regions of fre-quent induced seismicity where events are hours to daysapart pore pressures are not necessarily static at the onset ofsubsequent induced events [1 2] In terms of ground re-sponse for liqueable cohesionless soils excess pore pressuregeneration is relatively independent of loading frequencywith dissipation being a function of permeability [39 42]Moreover excess pore pressure ratios do not need to achieveunity to cause signicant strains within a cohesionlesscontinuum strains as low as 03 can indicate the onset ofuncontrolled degradation within the subsurface [39] isdegradation or strength reduction may cause dierentialsettlement beneath a structure leading to foundation damageor failures even though the physical structure would benegligibly aected by the induced seismic waveform Forexample a loose liqueable nonplastic silt has a cyclic re-sistance ratio CRR of 0187 at the onset of signicantstraining Figure 1 (a M75 tectonic event corresponds to 15equivalent loading cycles [43]) the CRR increases to ap-proximately 0294 for a single cycle equivalentus based onSeed and Idriss [44] and Seed et al [45] the smallermagnitude-induced event would have to yield approximately15 times increase in peak acceleration to initiate signicantsubsurface straining For tectonic events such acceleration isnot achieved with a decrease in earthquake magnitudeHowever for induced seismicity (1) illustrates that such anincrease in acceleration with a decrease in earthquake mag-nitude is possible due to the shallow hypocenter

A typical earthen structure may have a minimumthreshold equivalent acceleration of approximately 02 gbefore the onset of straining (damage) is believed to occurtypically referenced as 15 equivalent loading cycleserefore in the case of loose liqueable nonplastic silt lensa single-cycle equivalent event that is induced seismicevent would require an acceleration of approximately 030 gto have the same damage potential Peak accelerations inexcess of this example have been observed in induced eventsfor example mbLg 41 Timpson Texas with peak accelera-tions of up to 062 g [29] If the induced seismic eventequivalent loading cycles increase to four then the requiredacceleration to achieve the same 02 g threshold remainsrelatively unchanged at 027 g thus justifying a single in-duced event as impulse load Repetitive induced events canthen be treated as a low frequency loading equivalents witha sinusoidal maximum equivalent to the impulse

Eects on smaller structures from high frequencies (bothtemporal and spectral) not the amplitude of the accelera-tion can be observed at a signicant distance from theepicenter and would observationally manifest in intensityreports While aftershocks from tectonic events decrease inmagnitude induced seismicity magnitudes remain relativelyconstant for each subsequent event making the impulseload relatively constant with each event [1 2] us it is

misleading to compare tectonic earthquakes and inducedseismicity without accounting explicitly for variance inloading mechanisms In regions of frequent induced seis-micity structures subjected to repetitive impulse loadings donot consider soil fatigue states Such conditions are explicitlyaccounted in for other aspects of civil engineering for ex-ample trac vibration in bridge design in either design orassessment processes and should be included in discussionsof the subsurface damage potential for induced seismicitydue to the risk to the overall stability

ere are unknown eects that may increase the damagepotential from induced seismicity for example the largevertical acceleration component as observed in TimpsonTexas [29] Our understanding of seismic loading is based ontectonic events that manifest as large horizontal groundmotions with minimal inuence from the vertical compo-nent which is often ignored is change in loading di-rection alters the shearing axis and therefore the soilrsquoscapacity to resist the imparted load Further an appliedshear load propagating vertically from the subsurface ismore representative of an extension type loading this is theweakest axis for soil resistance and warrants further study

5 Hazard and Risk

Induced seismic events do not carry the same hazard as largetectonic equivalents In tectonic events the radial extent oflarge ground motions exceeds that of what has been ob-served in shallow induced seismicity erefore the asso-ciative risk to critical infrastructure of a single inducedseismic event would decrease in comparison based on howrisk is calculated [46]

Seismic Risk Seismic Hazard Θ Vulnerability (2)

e Vulnerability of any structure is a function of ex-posure (within the proximity of the seismic event such thatit may potentially be aected) fragility (susceptibility ofthe structure to the ground intensities) and consequence(socioeconomic impact should failure occur) [22] In (2) the

035

03

025

02

015

01

Cycli

c stre

ss ra

tio (C

SR)

CRR = 0294 Nndash0167

R2 = 0907

10 1001Number of equivalent cycles to the onset of uncontrolled

degradation (N)

Figure 1 e cyclic resistance to the onset of uncontrolleddegradation of a loose to medium dense nonplastic Rhode Islandsilt (after 40)

Advances in Civil Engineering 3

Seismic Hazard or probability of exceedance of a specifiedground motion intensity for tectonic events (the PGAPGV spectral content etc) can readily exceed that of in-duced events [1 2] on a per event basis However the closespatial proximity and repetitious nature of induced eventsactually increase the exposure or the chance that an inducedepicenter will occur within sufficient proximity to exceeda threshold acceleration by increasing the probability ofan event occurrence shown in the b-value for inducedevents [1 2]

Quinn and Taylor [38] illustrated that in the case ofearthen dams normal to slight increases in one hazard(eg the impounded water head) can reduce the requiredseismic hazard threshold for exceedance In this scenariothe Seismic Risk would be a joint probability function of theSeismic Hazard and the secondary hazard (eg floodevent) It is then possible that repetitive low magnitude-induced events combined with a secondary hazard result ina higher Seismic Risk or failure potential than a largertectonic event is may yield a situation where thestructural design is insufficient and the probability of oc-currence is greater for the joint-induced seismic-secondaryhazard event despite the structure being designed fora larger single tectonic event

6 Conclusions

e answer to ldquoCan repetitive small magnitude-inducedseismic events actually cause damagerdquo requires a betterunderstanding of the extent of failure modes (classic failureversus soil fatigue) and threshold limits within the seismichazard and vulnerability of structures ill-equipped towithstand seismic loading Further complicating thequantification of the Seismic Hazard for geoengineering-induced events is that the full extent of the hazard is not fullyknown and varies with changes in geoengineering activitieslocations and technologies [2] us making inducedseismic hazard maps and other measures is currently moresubjective than quantitative Furthermore the Vulnerabilityis complicated by the age of the infrastructure for exampledams locks levee and so on For example the US ArmyCorps of Engineers oversees maintains or operates over 700dams 14500 miles of levees and 220 locks [23] Most ofthese are aging facilities in need of constant repair andrehabilitation eleven of these locks are in excess of 100 yearsold [23] Such conditions lower the exceedance thresholdwithin the Seismic Hazard and increase the fragility withinthe Vulnerability thereby generating even greater SeismicRisk for small magnitude events both on single-event andmultiple event bases us a simplistic definitive statementof whether single or multiple small magnitudeinducedseismic events do or do not cause damage to critical in-frastructure cannot be justified on the basis of comparativemagnitudes between induced and tectonic events andwarrants additional study especially in respect to soil fa-tigue However recent observations and research suggest thelikelihood that these geoengineering-induced events can anddo cause detrimental degradation of the subsurface (dam-aging the overlying structure) is not insignificant

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e research was funded through the Assistant Secretary ofthe Army Acquisition Logistics and Technology (ASAALT)Military Engineering Direct Research program AT40ldquoRemote Assessment of Critical Infrastructurerdquo DirectorGeotechnical and Structures Laboratory US Army Engi-neer Research amp Development Center granted permissionto publish this research with unlimited distribution

References

[1] O-D S Taylor A P Lester and T A Lee ldquoHazard andrisk potential of unconventional hydrocarbon development-induced seismicity within the central United Statesrdquo NaturalHazards Review vol 16 no 4 p 04015008 2015

[2] O-D S Taylor A P Lester and T A Lee UnconventionalHydrocarbon Development Hazards within the Central UnitedStates Report 1 Overview and Potential Risk To InfrastructureERDCGSL TR-15ndash26 US Army Engineer Research andDevelopment Center Vicksburg MS USA 2015

[3] A McGarr ldquoMaximum magnitude earthquakes inducedby fluid injectionrdquo Journal of Geophysical Research SolidEarth vol 119 no 2 pp 1008ndash1019 2014

[4] G M Atkinson ldquoGround-motion prediction equation for small-to-moderate events at short hypocentral distances with appli-cation to induced-seismicity hazardsrdquo Bulletin of the Seismo-logical Society of America vol 105 no 2A pp 981ndash992 2015

[5] W L Ellsworth ldquoInjection-induced earthquakesrdquo Sciencevol 341 no 6142 p 1225942 2013

[6] T R Harper ldquoEffective stress history and the potential forseismicity associated with hydraulic fracturing of shalereservoirsrdquo Journal of the Geological Society vol 171 no 4pp 481ndash492 2014

[7] S E Hough L Seeber and J G Armbruster ldquoIntraplatetriggered earthquakes observations and interpretationsrdquoBulletin of the Seismological Society of America vol 93 no 5pp 2212ndash2221 2003

[8] E Brodsky and L Lajoie ldquoAnthropogenic seismicity rates andoperational parameters at the Salton Sea Geothermal FieldrdquoScience vol 341 no 6145 pp 543ndash546 2013

[9] H Davis KWCH12 News Earthquakes Take Toll on HarperCounty Courthouse June 2015 httpwwwkwchcomnewslocal-newsearthquakes-take-toll-on-harper-county-courthouse31183754

[10] C Frohlich C Hayward B Stump and E Potter ldquoeDallas-Fort Worth earthquake sequence October 2008 through May2009rdquo Bulletin of the Seismological Society of America vol 101no 1 pp 327ndash340 2011

[11] C Frohlich ldquoTwo-year survey comparing earthquake activity andinjection-well locations in the Barnett Shale Texasrdquo Proceedingsof the National Academy of Sciences Earth Planetary and At-mospheric Sciences vol 109 no 35 pp 13934ndash13938 2012

[12] C Frohlich and M Brunt ldquoTwo-year survey of earthquakesand injectionproduction wells in the Eagle Ford Shale Texasprior to the Mw48 20 October 2011 earthquakerdquo Earth andPlanetary Science Letters vol 379 pp 56ndash63 2013

[13] S Horton ldquoDisposal of hydrofracking waste fluid by injectioninto subsurface aquifers triggers earthquake warm in Central

4 Advances in Civil Engineering

Seismic Hazard or probability of exceedance of a specifiedground motion intensity for tectonic events (the PGAPGV spectral content etc) can readily exceed that of in-duced events [1 2] on a per event basis However the closespatial proximity and repetitious nature of induced eventsactually increase the exposure or the chance that an inducedepicenter will occur within sufficient proximity to exceeda threshold acceleration by increasing the probability ofan event occurrence shown in the b-value for inducedevents [1 2]

Quinn and Taylor [38] illustrated that in the case ofearthen dams normal to slight increases in one hazard(eg the impounded water head) can reduce the requiredseismic hazard threshold for exceedance In this scenariothe Seismic Risk would be a joint probability function of theSeismic Hazard and the secondary hazard (eg floodevent) It is then possible that repetitive low magnitude-induced events combined with a secondary hazard result ina higher Seismic Risk or failure potential than a largertectonic event is may yield a situation where thestructural design is insufficient and the probability of oc-currence is greater for the joint-induced seismic-secondaryhazard event despite the structure being designed fora larger single tectonic event

6 Conclusions

e answer to ldquoCan repetitive small magnitude-inducedseismic events actually cause damagerdquo requires a betterunderstanding of the extent of failure modes (classic failureversus soil fatigue) and threshold limits within the seismichazard and vulnerability of structures ill-equipped towithstand seismic loading Further complicating thequantification of the Seismic Hazard for geoengineering-induced events is that the full extent of the hazard is not fullyknown and varies with changes in geoengineering activitieslocations and technologies [2] us making inducedseismic hazard maps and other measures is currently moresubjective than quantitative Furthermore the Vulnerabilityis complicated by the age of the infrastructure for exampledams locks levee and so on For example the US ArmyCorps of Engineers oversees maintains or operates over 700dams 14500 miles of levees and 220 locks [23] Most ofthese are aging facilities in need of constant repair andrehabilitation eleven of these locks are in excess of 100 yearsold [23] Such conditions lower the exceedance thresholdwithin the Seismic Hazard and increase the fragility withinthe Vulnerability thereby generating even greater SeismicRisk for small magnitude events both on single-event andmultiple event bases us a simplistic definitive statementof whether single or multiple small magnitudeinducedseismic events do or do not cause damage to critical in-frastructure cannot be justified on the basis of comparativemagnitudes between induced and tectonic events andwarrants additional study especially in respect to soil fa-tigue However recent observations and research suggest thelikelihood that these geoengineering-induced events can anddo cause detrimental degradation of the subsurface (dam-aging the overlying structure) is not insignificant

Conflicts of Interest

e authors declare that they have no conflicts of interest

Acknowledgments

e research was funded through the Assistant Secretary ofthe Army Acquisition Logistics and Technology (ASAALT)Military Engineering Direct Research program AT40ldquoRemote Assessment of Critical Infrastructurerdquo DirectorGeotechnical and Structures Laboratory US Army Engi-neer Research amp Development Center granted permissionto publish this research with unlimited distribution

References

[1] O-D S Taylor A P Lester and T A Lee ldquoHazard andrisk potential of unconventional hydrocarbon development-induced seismicity within the central United Statesrdquo NaturalHazards Review vol 16 no 4 p 04015008 2015

[2] O-D S Taylor A P Lester and T A Lee UnconventionalHydrocarbon Development Hazards within the Central UnitedStates Report 1 Overview and Potential Risk To InfrastructureERDCGSL TR-15ndash26 US Army Engineer Research andDevelopment Center Vicksburg MS USA 2015

[3] A McGarr ldquoMaximum magnitude earthquakes inducedby fluid injectionrdquo Journal of Geophysical Research SolidEarth vol 119 no 2 pp 1008ndash1019 2014

[4] G M Atkinson ldquoGround-motion prediction equation for small-to-moderate events at short hypocentral distances with appli-cation to induced-seismicity hazardsrdquo Bulletin of the Seismo-logical Society of America vol 105 no 2A pp 981ndash992 2015

[5] W L Ellsworth ldquoInjection-induced earthquakesrdquo Sciencevol 341 no 6142 p 1225942 2013

[6] T R Harper ldquoEffective stress history and the potential forseismicity associated with hydraulic fracturing of shalereservoirsrdquo Journal of the Geological Society vol 171 no 4pp 481ndash492 2014

[7] S E Hough L Seeber and J G Armbruster ldquoIntraplatetriggered earthquakes observations and interpretationsrdquoBulletin of the Seismological Society of America vol 93 no 5pp 2212ndash2221 2003

[8] E Brodsky and L Lajoie ldquoAnthropogenic seismicity rates andoperational parameters at the Salton Sea Geothermal FieldrdquoScience vol 341 no 6145 pp 543ndash546 2013

[9] H Davis KWCH12 News Earthquakes Take Toll on HarperCounty Courthouse June 2015 httpwwwkwchcomnewslocal-newsearthquakes-take-toll-on-harper-county-courthouse31183754

[10] C Frohlich C Hayward B Stump and E Potter ldquoeDallas-Fort Worth earthquake sequence October 2008 through May2009rdquo Bulletin of the Seismological Society of America vol 101no 1 pp 327ndash340 2011

[11] C Frohlich ldquoTwo-year survey comparing earthquake activity andinjection-well locations in the Barnett Shale Texasrdquo Proceedingsof the National Academy of Sciences Earth Planetary and At-mospheric Sciences vol 109 no 35 pp 13934ndash13938 2012

[12] C Frohlich and M Brunt ldquoTwo-year survey of earthquakesand injectionproduction wells in the Eagle Ford Shale Texasprior to the Mw48 20 October 2011 earthquakerdquo Earth andPlanetary Science Letters vol 379 pp 56ndash63 2013

[13] S Horton ldquoDisposal of hydrofracking waste fluid by injectioninto subsurface aquifers triggers earthquake warm in Central

4 Advances in Civil Engineering

Arkansas with potential for damaging earthquakerdquo Seismo-logical Research Letters vol 83 no 2 pp 250ndash260 2012

[14] W Y Kim ldquoInduced seismicity associated with fluid injectioninto a deep well in Youngstown Ohiordquo Journal of GeophysicalResearch Solid Earth vol 118 no 7 pp 3506ndash3518 2013

[15] C D Klose ldquoHuman-riggered earthquakes and their impacts onhuman security achieving environmental security ecosystemservices and human welfarerdquo in NATO Science for Peace andSecurity Series- Human and Societal Dynamics vol 69 pp13ndash19P H Liotta Ed IOS Press Amsterdam Netherlands 2010

[16] L Seeber J G Armbruster and W Y Kim ldquoA fluid-injection-triggered earthquake sequence in Ashtabula Ohio implicationsfor seismogenesis in stable continental regionsrdquo Bulletin of theSeismological Society of America vol 94 no 1 pp 76ndash87 2004

[17] J H Healy WW Rubey D T Griggs and C B Raleigh ldquoeDenver earthquakesrdquo Science vol 161 no 3848 pp 1301ndash13101968

[18] C B Raleigh J H Healy and J D Bredehoeft ldquoAn exper-iment in earthquake control at Rangely Coloradordquo Sciencevol 191 no 4233 pp 1230ndash1237 1976

[19] G Atkinson K Assatourians B Cheadle and W GreigldquoGround motions for three recent earthquakes in WesternAlberta and Northeastern British Columbia and their implica-tions for induced-seismicity hazard in eastern regionsrdquo Seis-mological Research Letters vol 86 no 3 pp 1022ndash1031 2015

[20] G Atkinson H Ghofrani and K Assatourians ldquoImpact ofinduced seismicity on the evaluation of seismic hazard Somepreliminary considerationsrdquo Seismological Research Lettersvol 86 no 3 pp 1009ndash1021 2015

[21] Christian ScienceMonitor Scientists ldquoFrackingrdquo Should Be Partof Assessing Earthquake Hazards October 2014 httpwwwcsmonitorcomEnvironment20140501Scientists-Fracking-should-be-part-of-assessing-earthquake-hazards

[22] J K Mitchell and R A Green ldquoSome induced seismicity con-siderations in geo-energy resource developmentrdquo Geomechanicsfor Energy and the Environment vol 10 pp 3ndash11 2017

[23] E P Chamberlayne Risky Buisness ldquoFrackingrdquo and US ArmyInfrastructure Civilian Research Project Army War CollegeFellowUnited States ArmyWarCollege Carlisle PAUSA 2015

[24] R R Burchett K V Luza O J Van Eck and F W WilsonSeismicity and Tectonic Relationships of the Nemaha Uplift andMidcontinent Geophysical Anomaly (Final Project Summary)Vol 4 Special Publication 85-2 Oklahoma Geological SurveyNorman OK USA 1985

[25] K M Keranen H M Savage G A Abers and E S CochranldquoPotentially induced earthquakes in Oklahoma USA linksbetween wastewater injection and the 2011 Mw 57 earthquakesequencerdquo Geology vol 41 no 6 pp 699ndash702 2013

[26] KM KeranenMWeingarten G Abers B Bekins and S GeldquoSharp increase in central Oklahoma seismicity since 2008induced by massive wastewater injectionrdquo Science vol 345no 6195 pp 448ndash451 2014

[27] B Oskin Fracking-Linked Earthquakes May Strike Far FromWells Live Science May 2014 httpwwwlivesciencecom45322-fracking-wastewater-farther-earthquakeshtml

[28] C Ramsay 43 Magnitude Earthquake Hits Near RockyMountain House Global News August 2014 httpglobalnewscanews1501147earthquake-hits-northeast-of-rocky-mountain-house-power-outages-reported

[29] C FrolichW EllsworthW Brown et al ldquoe 17May 2012M48 earthquake near Timpson East Texas an event possiblytriggered by fluid injectionrdquo Journal of Geophysical ResearchSolid Earth vol 119 no 1 pp 581ndash593 2014

[30] J Malewitz After Surprise Quakes North Texans Speak ofImpact e Texas Tribune Austin TX USA June 2014 httpwwwtexastribuneorg20140103texans-seek-answers-drillings-link-earthquakes

[31] USGSmdashUS Geologic Survey Cherokee Oklahoma EarthquakeDid You Feel It Archive Page US Geological Survey RestonVA USA June 2015 httpearthquakeusgsgovearthquakesdyfieventsusc000tmebusindexhtml

[32] Associated Press Quake Slightly Damages Alfalfa CountyCourthouse Muskogee Phoenix June 2015 httpwwwmuskogeephoenixcomnewsoklahoma_newsquake-slightly-damages-alfalfa-county-courthousearticle_e199f496-adc4-11e4-884a-978d3fa3aa8ahtml

[33] D Lefler Fe Wichita Eagle 2014 Kansans Clean up afterMagnitude-48 Earthquake Shakes Wichita Southern Part ofState November 2014 httpwwwkansascomnewslocalarticle3847222html

[34] A Bickel Age Quakes Escalate Damage at Harper CoCourthouse at More Fan $11M Kansas Agland June 2015httpwwwkansasaglandcomnewsstateagnewsage-quakes-escalate-damage-at-harper-co-courthouse-at-morearticle_7d0f1168-4832-56a5-8236-2fe1f538590ahtml

[35] USGSmdashUS Geologic Survey Kansas 49 Earthquake USGeological Survey RestonVAUSA June 2015 httpearthquakeusgsgovearthquakeseventpageusc000swrugeneral_summary

[36] J MackMichigan Earthquake Causes Minor Building DamageNear Galesburg Epicenter Mlive June 2015 httpwwwmlivecomnewskalamazooindexssf201505michigan_earthquake_causes_minhtml

[37] USGSmdashUS Geologic Survey M42mdash8 km S of GalesburgUS Geological Survey Lansing MI USA June 2015 httpearthquakeusgsgovearthquakeseventpageus20002avhscientific_summary

[38] M C L Quinn and O-D S Taylor ldquoHazard topographyvisual approach for identifying critical failure combinationsfor infrastructurerdquo Natural Hazards Review vol 15 no 4p 04014012 2014

[39] O-D S Taylor ldquoUse of an energy-based liquefaction approach topredict deformation in silts due to pile drivingrdquo PhD dissertationUniversity of Rhode Island Kingston RI USA 2011

[40] J J Bommer B Dost B Edwards et al ldquoDeveloping anapplication-specific ground-motion model for induced seis-micityrdquo Bulletin of the Seismological Society of Americavol 106 no 1 pp 158ndash173 2016

[41] D E Hudson Reading and Interpreting Strong MotionAccelerograms Earthquake Engineering Research InstituteBerkeley CA USA 1979

[42] M F Riemer W B Gookin J D Bray and I Arango Effectsof Loading Frequency and Control on the Liquefaction Be-havior of Clean Sands Geotechnical Engineering Rep UCBGT94-07 University of California Berkeley CA USA 1994

[43] R Green and G Terri ldquoNumber of equivalent cycles concept forliquefaction evaluationsmdashrevisitedrdquo Journal Geotechnical andGeoenviromental Engineering vol 131 no 4 pp 477ndash488 2005

[44] H B Seed and I M Idriss ldquoSimplified procedure for evaluatingsoil liquefaction potentialrdquo Journal of the Soil Mechanics andFoundations Division vol 97 no SM9 pp 1249ndash1273 1971

[45] H B Seed I M Idriss F Makdisi and N Banerjee Repre-sentation of Irregular Stress Time Histories by Equivalent UniformStress Series in Liquefaction Analysis Tech Rep EERC 75ndash29Earthquake Engineering Research Center College of Engi-neering University of California Berkeley CA USA 1975

[46] ZWang ldquoSeismic hazard assessment issues and alternativesrdquoPure and Applied Geophysics vol 168 no 1-2 pp 11ndash25 2010

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