Simulating Earthquake Rupture and Off-Fault Fracture Response: Application to the Safety Assessment of the Swedish Nuclear Waste Repository

Handle URI:
http://hdl.handle.net/10754/575626
Title:
Simulating Earthquake Rupture and Off-Fault Fracture Response: Application to the Safety Assessment of the Swedish Nuclear Waste Repository
Authors:
Falth, B.; Hokmark, H.; Lund, B.; Mai, Paul Martin ( 0000-0002-9744-4964 ) ; Roberts, R.; Munier, R.
Abstract:
To assess the long-term safety of a deep repository of spent nuclear fuel, upper bound estimates of seismically induced secondary fracture shear displacements are needed. For this purpose, we analyze a model including an earthquake fault, which is surrounded by a number of smaller discontinuities representing fractures on which secondary displacements may be induced. Initial stresses are applied and a rupture is initiated at a predefined hypocenter and propagated at a specified rupture speed. During rupture we monitor shear displacements taking place on the nearby fracture planes in response to static as well as dynamic effects. As a numerical tool, we use the 3Dimensional Distinct Element Code (3DEC) because it has the capability to handle numerous discontinuities with different orientations and at different locations simultaneously. In tests performed to benchmark the capability of our method to generate and propagate seismic waves, 3DEC generates results in good agreement with results from both Stokes solution and the Compsyn code package. In a preliminary application of our method to the nuclear waste repository site at Forsmark, southern Sweden, we assume end-glacial stress conditions and rupture on a shallow, gently dipping, highly prestressed fault with low residual strength. The rupture generates nearly complete stress drop and an M-w 5.6 event on the 12 km(2) rupture area. Of the 1584 secondary fractures (150 m radius), with a wide range of orientations and locations relative to the fault, a majority move less than 5 mm. The maximum shear displacement is some tens of millimeters at 200 m fault-fracture distance.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Environmental Science and Engineering Program; Earth Science and Engineering Program
Publisher:
Seismological Society of America (SSA)
Journal:
Bulletin of the Seismological Society of America
Issue Date:
9-Dec-2014
DOI:
10.1785/0120140090
Type:
Article
ISSN:
0037-1106
Sponsors:
The results presented in this article are based on work funded by the Swedish Nuclear Fuel and Waste Management Co (SKB). We thank the associate editor and two anonymous reviewers for their comments and suggestions that helped improve the manuscript.
Appears in Collections:
Articles; Environmental Science and Engineering Program; Physical Sciences and Engineering (PSE) Division; Earth Science and Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.authorFalth, B.en
dc.contributor.authorHokmark, H.en
dc.contributor.authorLund, B.en
dc.contributor.authorMai, Paul Martinen
dc.contributor.authorRoberts, R.en
dc.contributor.authorMunier, R.en
dc.date.accessioned2015-08-24T08:34:30Zen
dc.date.available2015-08-24T08:34:30Zen
dc.date.issued2014-12-09en
dc.identifier.issn0037-1106en
dc.identifier.doi10.1785/0120140090en
dc.identifier.urihttp://hdl.handle.net/10754/575626en
dc.description.abstractTo assess the long-term safety of a deep repository of spent nuclear fuel, upper bound estimates of seismically induced secondary fracture shear displacements are needed. For this purpose, we analyze a model including an earthquake fault, which is surrounded by a number of smaller discontinuities representing fractures on which secondary displacements may be induced. Initial stresses are applied and a rupture is initiated at a predefined hypocenter and propagated at a specified rupture speed. During rupture we monitor shear displacements taking place on the nearby fracture planes in response to static as well as dynamic effects. As a numerical tool, we use the 3Dimensional Distinct Element Code (3DEC) because it has the capability to handle numerous discontinuities with different orientations and at different locations simultaneously. In tests performed to benchmark the capability of our method to generate and propagate seismic waves, 3DEC generates results in good agreement with results from both Stokes solution and the Compsyn code package. In a preliminary application of our method to the nuclear waste repository site at Forsmark, southern Sweden, we assume end-glacial stress conditions and rupture on a shallow, gently dipping, highly prestressed fault with low residual strength. The rupture generates nearly complete stress drop and an M-w 5.6 event on the 12 km(2) rupture area. Of the 1584 secondary fractures (150 m radius), with a wide range of orientations and locations relative to the fault, a majority move less than 5 mm. The maximum shear displacement is some tens of millimeters at 200 m fault-fracture distance.en
dc.description.sponsorshipThe results presented in this article are based on work funded by the Swedish Nuclear Fuel and Waste Management Co (SKB). We thank the associate editor and two anonymous reviewers for their comments and suggestions that helped improve the manuscript.en
dc.publisherSeismological Society of America (SSA)en
dc.titleSimulating Earthquake Rupture and Off-Fault Fracture Response: Application to the Safety Assessment of the Swedish Nuclear Waste Repositoryen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentEnvironmental Science and Engineering Programen
dc.contributor.departmentEarth Science and Engineering Programen
dc.identifier.journalBulletin of the Seismological Society of Americaen
dc.contributor.institutionClay Technol AB, S-22370 Lund, Swedenen
dc.contributor.institutionUppsala Univ, Dept Earth Sci, S-75236 Uppsala, Swedenen
dc.contributor.institutionSwedish Nucl Fuel & Waste Management Co, S-10124 Stockholm, Swedenen
kaust.authorMai, Paul Martinen
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