ML20138P210
| ML20138P210 | |
| Person / Time | |
|---|---|
| Issue date: | 12/09/1985 |
| From: | Alterman I NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Beratan L NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| References | |
| NUDOCS 8512240385 | |
| Download: ML20138P210 (22) | |
Text
{{#Wiki_filter:, . . J"' DEC 0 01985 MEMORANDUM FOR: Leon Beratan, Chief Earth Sciences Branch Division of Radiation Programs and Earth Sciences, RES THRU: Andrew Murphy, Section Leader Earth Sciences Branch Division of Radiation Programs and Earth Sciences, RES FROM: Ina B. Alterman Earth Sciences Branch Division of Radiation Programs and Earth Sciences, RES
SUBJECT:
REPORT OF TRIP TO GE0 LOGICAL SOCIETY OF AMERICA ANNUAL MEETING, OCTOBER 28-31, 1985 At the annual meeting of the Geological Society of America, October 28-31, 1985, I attended several presentations given by NRC contractors, former NRC contractors, or others on topics of interest to the NRC. The following briefly summarizes some of the relevant presentations: Talwani, et. al.: The author presented a variety of geophysical and seismic data, and some stratigraphic determinations from the Charleston, S.C., area that resulted in defining a NW-trending graben bounded on one side by the Ashley River fault and cut by the NE-trending Woodstock fault. Isoseismals appear to define the graben. Paleoliquefaction studies and carbon dati.ig suggest a recurrence interval of 1500-1700 yrs for the Charleston earthquake. The authors suggest that the two faults may have been involved in the Charleston 1886 earthquake. Colquhoun, et. al.: Sea level changes along coastlines can be distinguished by causative mechanisms, such as isostasy, eustacy (sea water volumetric changes) or tectonics, based on the known history, sediment structure and distribution, and comparison of world-wide sea level curves. The author focused on changes near Charleston, S.C. showing sporadic tectonic movements in the graben defined by Talwani which overprint larger scale eustatic movements. The total picture indicates change in rate of eustatic sea level rise from rapid to slow at about 6000 YBP. 8512240385 851209 PDR RES 8512240385 PDR
l t Leon L. Beratan 2 DEC 0 S 1985 Stapor, et al.: A significant (lm) rise in sea level in the Charleston Coastline area at about 1100YBP was determined by coastline sediment features such as beach ridges, sand dunes and marsh-buried onshore trees in roughly the same area defined by Talwani et al. as a graben. The authors state that they recognize a similar sea level rise at the same time in southwest Florida. Although drawing no conclusions about the cause, the implication was a eustatic rise or an epeirogenic (large scale downwarp of the coastline) event. It is rather coincidental, I thoc?:t, that they should recognize an abrupt short term sea level rise within the same general area that Colquhoun et al. recognize tectonic fluctuaticns of a graben. Jibson and Keefer studied slope stability and landsliding in the New Madrid seismic zone. They were able to identify many old slides showing block t mnslations. Through field and historical data, statistical analysis of distribution of large slides relative to the New Madrid 1811-1812 epicenters, and site-specific seismic analysis, they were able to determine that young slides resulted from river bank undercutting and that, while slopes were presently stable, a critical ground acceleration of .179 would produce large scale landsliding in the study area. Schmoll et al.: An attempt at developing a methodology for seismic zonation in the Anchorage, Alaska, area focused on properties of the strata which are poorly known and the distribution of which is almost unknown. The presentation had little more information than the abstract, except for maps and a rough stratigraphic section. The idea is at an early stage. McCarten and Gettings: Circular gravity and magnetic anomalies and subsurface structural features in the Southeast Georgia Embayment point to a mafic pluton 3 km thick, 10 km in diameter, 1.5 km below the surface of the Coastal Plain and bounded by faults. Upwarp of"the "J" reflector offshore, subsurface sedimentary characteristics of late Tertiary sediments, and geothermal gradients suggest a late Tertiary age of 20-30 million years before the present (MYBP). The pluton is located between Charleston and the Savannah River on the South Carolina Coast. Charlie et al.: An experimental attempt to understand conditions necessary to induce liquefaction involved both a laboratory compressional apparatus to simulate compressional waves and a finite-difference model. The authors observed that ordinary explosives could produce sand boils and geysers. In the lab, they measured the number of axial compressive stress pulses and the pore water pressure increases necessary to induce liquefaction using a compressive stress of 10,000 PSI, in sand. They found the sand liquefied at a .1% strain with peak particle velocity of I cm/sec. They ran several tests but did not vary the type of material. This will be done in future tests.
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Leon L. Beratan 3 DEC 0 f,1985 l
- Isfording and Flowers: The possibility of dissolution in non-carbonate terrains leading to surface collapse features and subsidence of structures with resultant structural damage and foundation fractures was described by the authors. The non-carbonate stratum was a Kaolinite (clay) cemented sandstone in which the clay was being transformed to gibbsite with a concomitant reduction in volume, causing compaction phenomena, small surface depressions, and other effects leading to structural damage. The dissolution of non-carbonate foundations has not been a major consideration in site investigations.
- Van Arsdale and Sergeant: In a poster session the authors showed ' trench logs and photographs of Plio-Pleistocene strata overlying Paleozoic limestone in which faults within the Kentucky River Fault Zone projected up from the bedrock through the terrace and alluvial deposits. One northwest-trending fault near Winchester, KY, came to within two feet of the surface right up to the plowed zone. The possible recent displacement of the Kentucky River Fault Zone is of significance in the way that the Meers Fault is significant. Recent faulting in Eastern U.S. has not been proven heretofore.
Zoback et al.: The authors have revised their well-known stress-province map of the U.S., eliminating the Atlantic Coast stress province, formerly determined to be subject to a NW-oriented maximum horizontal compressive stress normal to the NE-trending compressive stress of the rest of Eastern North America. The new revision in which the east coast is consistent in stress orientation with the Eastern U.S. is based on borehole breakouts, hydrofracturing, and reevaluation of NY-NJ focal mechanisms. Enclosed are the published abstracts of these talks. Ina B. Alterman, Geologist Earth Sciences Branch, DRPES
Enclosures:
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r __ d . RESULTS OF RECENT SEISM 0 TECTONIC STUDIES IN DIE N? 74081! CHARLESTON AREA TALWANI, Pradeep; COLQUHOUN, D.J. and LENNON, Gered, Geology j Department, University of South Carolina, Columbia, S.C. 29208. i In order to understand the cause and nature of seismicity near Charleston we have examined an assortment of data. These include relocated hypocenters, potential field, seismic, shallow stratigraphic and releveling data, together with seismicity, releveling and paleo-seismicity data. An evaluation of these data suggest the following:
- 1. A NW trending graben, of which one flank is possibly related g to the buried (4-7 km) Ashley River f ault (ARF). '
- 2. The seismic reflection and hypocentral data suggest that the ARF is cut by the NNE trending Woodstock f ault, which is downdropped .
to the NW.
- 3. The block defined by the Woodstock and ARF is postulated to represent the seismogenic feature responsible for seismicity.
- 4 The pattern of isoseismals of current felt earthquakes resembles the outline of the NW trending graben.
- 5. Historical and other data suggest that both sources were active in 1886.
- 6. The results of paleoseismological studies suggest a recurrent time of 1500-1700 Y. for similar events.
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COMPARISON O STATIC SEA NE0 TECTONIC DISTORTION WITH ISO- AND EU- fj! 79 COLQUOH
'VELS N, DonaldIN HID - IATE HOLOCENE SOUTH CAROLINA J.,
and TALWANI, Pradeep. LENNON, Gered,POLEY, Kat ROOKS, Mark, Geology Dept., Univ. of S.C., Columbia,SC 292 8 All coas ines reflect isostatic, (ice or water loading and unloading , tectonigg (f olding and f aulting) and neotectonic (migration of the geoid) pisto'rtions through time. are ugque and no general curve exists.Thus Holocen?" sea-level change curves (true changes in sea level Nevertheless eustatic changes itsell through ice / water ratios on conti-nent vol land masses, volume changes in ocean basins, specific gravity or c changes in amount of ocean water) exist, est mated. and can be observed and th They are probably related to global climatic changes within d Holocene tinant prior through the Oligocene, and to sea-floor spreading as well, to late Eocene. ( seloped through marsh stratigraphic and archeologicOur sea level change cur
' t'een Georgetown and Savannah. indicators Be-2 rope was noted. Goincidence in time of change in NW Some of the smaller 11uctuations were thought eusta-EEI vetailed~ studies (1983-85)
'nd South Edisto reveal rapid sea riseat Winyah Bay, Charleston and North 5000 B.P. (cms /100 yrs) (meters /1000 yrs) slowing near cntinuing to the present.with small fluctuations (amplit .de uncertain)
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- Tectonic distortion in our study area oc-1 urs in a crnhen landward between Goose Creek ~and Kiawah Island and
- 1nded near Summerville. Sporadic movement began in the Jhanetran and i
ontinues through the 1970's with movement remaining sLmiliar. In pite of this, archeologic indicators (thought to reflect custatic ( hanges) within and without the graben express similiar clustering of m tes, as does timing of rapid to slow change. Thus these custatic ti ements generally exceed neotectonic, tectonic and isostatic distor-B. , of this Coastal Plain, and prove eustatic rate change near -6000 tuat (observed in the Pacific and elsewhere) and small eustatic fl ns both here, N.W. Europe, Richmond Gulf and elsewhere. I a
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t RRIER-ISLAND PROGRADATION AND THE 1100N2 BP 89 SEA-LEVEL EVENT IN CENTRAL SOUTH CAROLINA STAPOR, Frank W., Exxon Prod. Research Co., Box 2189, Houston, TX 77001; MATHEWS, Thomas D., MRRI, Box 12559, Charleston, SC 29412, and LINDSFORS-KEARNS, Fonda L., Survey, LSU Box G, Baton Rouge, LA 70893 Louisiana Geological Botany, Seabrook, Kiawah, and the seaward progradation during the period !!00-600 BP. Isle of Palms experienced ridges of Seabrook, Kiawah, and the Isle of Palms indicate direct onshore-T while the curved, spit-type ridges of Botany indicate littoral-transport. Beach locally with poorly developed dunes. Because thes quite similar to that of ridges formed over the past 50 years, sea level their formation was at a position essentially equal to that of today. The marsh-buried beach ridges at Edisto Beach that were deposited about 1300 BP and the marsh-buried beach ridges at St. Phillips Island that contain 1000 BP pine stumps suggest a sea-level position somewhat lower than presen Thus, a significant rise in sea-level occurred at about much as 1 m, that was quickly followed, within 2001100 BP, perhaps as 14 initiation and/or progradation of Botany, C-years, by the hypothesized Seabrook, and Kiawah. that the adjustment of the nearshore It is necessitated by this rise was characterized by accelerated ansbore- as wellequ of sand in this region.as littoral-transport, because the nearshore and The onset of progradation resulting from this sea-level event can is dependent vary from island on the local rate at which sediment is supplied and this to island. regradation has ceased and now In central South Carolina island-wide ir ediately adjacent to ebb-tidal deltas. growth occurs only in those portions and Florida. silar in magnitude has been identified by the authors in southw
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7% DSLIDES JIBSON, IN THE Randall NEW MADRID SEISMIC ZONE Na 79196 W., KEEFER, David K., U.S. Geological Survey, Resto During U.S. Geological Survey, Menlo VA k, 22092, and CA 94025 the New Mississippi alluvial Madrid earthquakes plain in of 1811-12, bluffs scale landsliding. the epicentral region unde rdering the ent large-Between Cairo,111. and Memphis, Tenn., e mapped 221eroded, old, large (greater coherent block than 200 ft wide) landslides of three : typ (1) and (3) young, fresh slumps slides that and slumps; (2) old earth lows; and are the only landslides present along such bluffs. occur only along near-riv oldHistorical coherent slides accounts and field and earth flowsevidence date to the indicate 1811-12 that 1 ea most or rthquak a nd that the only currently active, large-scale landsliding in th area occurs along bluffs bordering the river. Statistical analyses indicate that the regional distribution of these young, near-river slumps undercutting.relates most strongly to slope steepness, a result of fluvial Analysis of ol d coherent slides and earth flows indicates slope height,thatbutlandslide that proximity distribution to is most strongly affected by earthquakes also has a significant effect.the hypocenters of the 1811-12 Slope-stability analyses of an old coherent slide and an earth flo selected as representative of the principal kinds of landslid s present indicate that both were stable in aseismic conditions e en when water tables were at highest possible levels . Newmark displacement analysis shows that ground shaking in 1811-12 would a that suchHowev failure in both slides. cause large displacements leading to cata rophic-These results indicate that n large-(mbrtaquakes landsliding in much of the study area is likel S.0) earthquakes may also trigger landslides at so . Moderate locations. TW % *% e e.amop gg g m
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, .. . .. a - . .- a SEISMOTECHNISTRATIGR APHIC CELLS: AN APPROACH TO THE ANALYSIS OF SUBSURFACE GE0 LOGY AT ANCHORAGE, N? 5814 ALASKA, FOR USE IN SEISMIC ZONATION STUDIES SCHMOLL, Henry R. , 00VM, Jack K., and ESPINOSA, Al varo F. ,
U.S. Geological Survey, Box 25046, MS 972. Denver, CO 80225 Metropolitan Anchorage, Alaska, at the eastern margin of the upper Cook Inlet basin, is underlain by eastward-thinning sedimentary rock and surficial deposits of Cretaceous through Holocene age that overli - a basement complex of metamorphic and (or) plutonic rocks of mainly Mesozoic age. Cook Inlet basin lies atop an active Benioff zone and is subject to major earthquakes. Synthesis of lithologic, thickness, geotechnical, and shear-wave data is needed to achieve a realistic seismic-zonation program for the region. Present knowledge of the subsurface, based largely on borehole data of uneven distribution and quality, decreases exponentially with depth. Limited geologic and seismic cross-section data and knowledge of regional geology suggest a preliminary model useful for identifying data acquisition needs. The model is illustrated by the rutrix shown below. The rows represent five numbered, wedge-shaped, subhorizontal stratigraphic units that comprise basement (1); shale (2); silt , clay , and santistone (3); and older (4) and younger (5) Pleistocene glacial deposits including coarse (c) and fine (f) members that differ by age in character and distribution. The columns represent seven G F E D C B A lettered seismotechnistratigraphic cells 2.7 2.1 1.5 0.9 0.5 0.1 0.02 of different average thickness above Sc 3T W TE Sc F Sc basement, given in kilometers. Each cf 4f 4fc 4c 4c Ac 1 cell is variably narrow and relatively 3 3 3 3 1 long, and includes a unique combination 2 2 2 1 of elements that are segments of the 1 1 1 1 stratigraphic units. a-I
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/ s Id3 71760 STR ATIGJKIHIC AND GEOPHYSIC BEAUFORT, S. ALC. EVIDENCE FOR
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INTRUSION NEAR A TERKARY CCARTAN, Lucy, and GETTINGS, Mark E., , National Center,, U. S. Geological Survey, 'N Reston, VA 22092 10 km in diameter at 1.5 km \ mafic intrusion aboutstrong positive gravity and g depth is indicated by a closed structural high in magnetic anomalies and limestone near Beaufort, S. C. overlying upper Eocene Sediments of Oligocene age northeast of Beaufort and of Miocene age to the west and southwest indicate that the "Bea u fo r t high" divided the Southeast Georgia Embayment The into two sub-basins by late Oligocene time. stratigraphic relations and elevated geothermal gradients suggest an ageofofthe 20-30 Ma forhigh Beaufort the through intrusion. Maintenance incursions implies continued time despite several marine uplift, probably due to effects of Intrusionsthe intrusion withand 1 Tertiary compressional warping. similar geophysical signatures are commonest inthe the southeast but are also present elsewhere along across Seismic profiles Atlantic continential margin. the Clubhouse Crossroads deep corehole, the anomalies at 60 km north of Beaufort , show a flat Jurassic reflector,l Jurassic or older. so the intrusive 175 km rocks northeastthere of are Beaufort, ashows seismic However, an line[/ crosting one of tne offshore anomalies Substantiat on intrusion doming upfor Cenozoic sediments. the Beaufort pluton would of a Tertiary age significantly change the current models of the Tert ary Georgia Embaymen,t'.
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m INVESTIGATION OF COMPRESSIONAL WAVE-INDUCEo LI EFACTION N- 72 _ CHARLIE, W. A. , Civil Engineering Dept. , Colorado State Universi Ft. Collins, CO 80523; DOEHRING, D.0., Earth Resources Dept. , j Colorado State University, Ft. Collins, C0 80523; VEYERA, G.E., g Civil Engineering Dept., Colorado State University, Ft. Collins, CO 80523 Although most effort has been directed toward the study of liquefaction ( resulting from seismically-induced shear waves, natural and man-induced compressional waves are aise capable of liquefying saturated sediments. The state-of-the-art for predicting such phenomena is at best limited. Although some empirical scaling factors have been determined from field tests, theoretical approaches are almost non-existent and have not been verified by experimental testing. A reliable means of predicting compressional wave liquefaction potential should find applications in mining, geophysical surveying, construction and the military. We have taken two approaches, a. laboratory physical model and a finite difference computer model. Both techniques allow for the use of a wide variety of materials and initiating forces and yield porewater pressure response. Our laboratory model consists of a compressed air cannon that propels a projectile into the sample. Transducers monitor strain and porewater pressure every fifty thousandths of a second for two seconds. The computer model is based on Newton's Second Law of nation and couples a simple analytic locking model, to simulate the hysteretic behavior of the sediment skeleton, with a linear model to simulate the elastic behavior of the fluid. Our laboratory and computer models produce nearly identical results and both compare favorably with the meager empirical data available in the Rus and European literature. _ IHE ROLE OF por,eangorye me,nn w y ~ ,<-{7 p l l l
SUBSIDENCE PROBLEMS RELATED TO THE DEVELOPMENT OF 64757 SILICICLASTIC KARST ON THE CITRONELLE FORMATION OF SOUTHWESTERN ALABAMA iversity ISPHORDING, Wayne C., Department of Geology and Geography, of South Alabama, Mobile, AL 36688 and FLOWERS, George C., Depart-ment of Geology, Tulane University, New Orleans, LA 70118 The irreversible transformation of kaolinite to gibbsite and the c n-comitant negative volume change associated with the reaction has re ul-ted in residential structural damage in Mobile, Alabama. Failure o the insurance company to honor damage resulting from a " sinkhole col-lapse clause" resulted in litigation. The main points of contention in the trial were: (1) were the small depressions in the owner's yard caused by dissolution of material, resulting in the formation of subter anean voids?, (2) does the language used in the policy, i.e. "We cover for damages caused by sinkhole collapse due to the dissolution of lime-stone or similar rock formations." mean that because the Citronelle Sand h a rock formation (and assuming point (1) can be proved) that the resident should recover for damage to his house? Evidence introduced for the plaintiff included X-ray diffractograms, SEM photographs and grain size analyses. A summary of literature on the development of karst in non-carbonate terranes was also produced (e.g., quartzite karst from Venezuela, volcanic karst in New Mexico and later-ite karst from Australia. X-ray diffractograms indicated that gibbsite was being formed in the vadose zone; SEM photograps clearly revealed the presence of euhedral gibbsite crystals on both quartz grains and kaolin-ite. Size analyses were offered to disprove the allegation that the subsidence was a piping effect caused solely by removal of the silt com-ponent. Mass-balance equations and chemical analyses of groundwater were used to demonstrate that not only was kaolinite altering to gibben site, causing loss of volume, but that some quartz was also being t in into solution. After consideration of the evidence, the jury fou favor of the plaintiff and the resident was compensated for dam ,e.
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RIVER FAULT ZONE OF EAST-CENTRAL KENTUCKY ' VanArsdale, Roy B., Geology Department, University of Arkansa Fayetteville, AR 72701 and Sergeant, Richard E., Kentucky Ce - logical Survey, Lexington, KY 40506 Numerous f aults of the Kentucky River f ault zone are partially overlab - by Pliocene-Pleistocene terraces along the Kentucky river in east- 5 central Kentucky. Preliminary drilling and electrical resistivity surveys suggest that a number of the faults have been active since the deposition of the terraces. From these preliminary surveys 4 sites were selected and 9 trenches were excavated. Of these 9 trenches, 4 revealed f aulted and/or folded terrace sediments. One trench was excavated across a N40W trending fault in southern Clark County, cutting 3m deep into a 10m thick terrace. A monoclinal flexure, clay dikes, an asymmetric anticline, and a thrust f ault which of f set a soil ped all were exposed in the trench wall. A second trench across this f ault revealed a reverse fault which displaced the bedrock and the overlying terrace sediments by im. The third trench was excavated across a N60E trending fr. ult in northern Madison County, exposing folded and faulted Lexington Limestone, overlain by alluvium-colluvium. A line of charcoal f ragments, a line of barite nodules, and an underlying clay horizon in the alluvial-colluvial section appear to have locally folded with the underlying bedrock. Nearby, a fourth trench was excavated across another N60E trending fault revealing terrace folding and apparent faulting with im of reverse displacement. Comparison of the 9 trenches indicates that the folding and fault ing of the terrace deposits is tectonic in origin and that the Kentu y River fault zone has been active within the last 5 million years a probably within the last one million years. Recognition of relat ely young f ulting in Kentucky suggests that other mid-continent fa ts should b studied for recent displacement. EXPERIMENTAL SIUDY OF BONIN ' . " N- 62917 VAN DER 1AAN, Sieger R. , FLOWER, M1rtin F.J. ,
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s (615 AssESSENT OF THE STATE OF STRESS IN THE ATLANTIC COAST REGION N~ 64272 20BACK, Mary Lou, U.S. Geological Survey, 345 Middlefield Rd., 3 Menlo Park, CA 94025, 20BACK, Mark D., Dept. of Geophysics, p, Stanford Univ. , Stanford, CA 94305, DART, Richard, U.S. Geological Survey, DFC, Denver, CO 80225 ,ique n the Results of previous studies have suggested that a zone of NW-oriented tural compression exists along the Atlantic seaboard of the U.S. in contrast
- pths, to the NE-to ENE-oriented maximum horizontal stresses found throughout y and much of the midcontinent of North America. Poorly constrained Q of earthquake focal mechanisms and late Tertiary offsets across reverse move
(?) faults were the primary evidence for this conclusion. New stress s in data, however, cast serious doubt on the existexe of a distinct situ Atlantic coast stress province and suggest that the stress state will characterizing the midcontinent region may be cantinuous into the iety midplate region of the western north Atlantic. These new data include: 1) analysis of borehole elongations (" breakouts") from d2*P exploration wells on the U.S. continental shelf which indicate a llow compressive stress orien the area (6 wells), N 55*-70}ation of approximately E-W in the Georges bank and E in the Baltimore Ca1 yon field (13 wells), ical and N 40* E in the southeast Georgia embayment (1 well); 2) borehole sway elongation analysis of about 20 wells in southeastern Canada and on the smic Scotian shelf indicating a N 50*-55* E compressive stress orientation (Plumb and Cox,1984, EOS, p.1081-1082); 3) better-cons trained eartnquake focal mechanisms obtained recently (Statton and others 1982, Eq. Notes, v. 53, p. 36; Talwani,1982, GE0 LOGY, v.10, p. 654-658) and a re-analysis, including error assessment, of previous focal mechanisms in the New York-New Jersey area (Quittmeyer and others 19PS, Eq. Notes, in press); and 4) hydraulic fracture measurements and borehole I elongations in,a 1 km deep well near the Ramapo fault in NY which suggest a N 55 E + 10 maximum horizontal compressive stress orientation. - l i
Leon L. Beratan 3 DEC 0 f,1985
- Isfording and Flowers: The possibility of dissolution in non-carbonate terrains leading to surface collapse features and subsidence of structures with resultant structural damage and foundation fractures was described by the authors. The non-carbonate stratum was a Kaolinite (clay) cemented sandstone in which the clay was being transformed to gibbsite with a concomitant reduction in volume, causing compaction phenomena, small surface depressions, and cther effects leading to structural damage. The dissolution of non-carbonate foundations has not been a major consideration in site investigations.
Van Arsdale and Sergeant: In a poster session the authors showed trench logs and photographs of Plio-Pleistocene strata overlying Paleozoic limestone in which faults within the Kentucky River Fault Zone projected up from the bedrock through the terrace and alluvial deposits. One northwest-trending fault near Winchester, KY, came to within two feet of the surface right up to the plowed zone. The possible recent displacement of the Kentucky River Fault Zone is of significance in the way that the Meers Fault is significant. Recent faulting in Eastern U.S. has not been proven heretofore. Zoback et al.: The authors have revised their well-known stress-province map of the U.S., eliminating the Atlantic Coast stress prov We, formerly determined to be subject to a NW-oriented maximum horizontal cong m u1ve stress normal to the NE-trending compressive stress of the rest of Eastern North America. The new revision in which the east coast is consistent in stress
, orientation with the Eastern U.S. is based on borehole breakouts, hydrofracturing, and reevaluation of NY-NJ focal mechanisms.
Enclosed are the published abstracts of these talks. Ina B. Alterman, Geologist Earth Sciences Branch, DRPES
Enclosures:
As stated cc: A. Murphy S. Brocoum L. Reiter P. Sobel R. Rothman G. Giese-Koch Distribution /R-2811: RMinogue Econti Circ DCS/ DJ /(ChronDross LBeratan IAlterman ESB Sbj/Rd KGoller AMurphy ES $kf IAl eYman ESB:R AMurphy /L/ 6 /85 n /o 6/85
j %. - s I4, 4 DEC 0 91985 y MEMORANDUM FOR: Leon Beratan, Chief Earth Sciences Branch Division of Radiation Programs and Earth Sciences, RES THRU: Andrew Murphy, Section Leader Earth Sciences Branch Division of Radiation Programs and Earth Sciences, RES FROM: Ina B. Altennan ; Earth Sciences Branch Division of Radiation Programs and Earth Sciences, RES
SUBJECT:
REPORT OF TRIP TO GE0 LOGICAL SOCIETY OF AMERICA ANNUAL MEETING, OCTOBER 28-31, 1985 l At the annual meeting of the Geological Society of America, October 28-31, 1985, I attended several presentations given by NRC contractors, former NRC contractors, or others on topics of interest to the NRC. P The following briefly summarizes some of the relevant presentations: i
~
Talwani, et.'al.: The author presented a variety of geophysical and seismic data, and some stratigraphic determinations from the Charleston, S.C., area that resulted in defining a NW-trending graben bounded on one side by the Ashley River fault and cut by the NE-trending Woodstock fault. Isoseismals appear to define the graben. Paleoliquefaction studies and carbon dating suggest a recurrence interval of 1500-1700 yrs for the Charleston earthquake. The authors suggest that the two faults may have ' been involved in the Charleston 1886 earthquake. Colquhoun, et. al .: Sea level changes along coastlines can be , distinguished by causative mechanisms, such as isostasy, eustacy (sea water volumetric' changes) or tectonics, based on tne known history, sediment structure and distribution, and comparison of world-wide sea - level curves. The author focused on changes near Charleston, S.C. showing sporadic tectonic movements in the graben defined by Talwani which overprint larger scale eustatic movements. The total picture indicates change in rate of eustatic sea level rise froa rapid to slow at about 6000 YBP. l
L.e '1 , ge DEC 0 S 1985 I Leon L. Beratan 2
- Stapor, et al.: A significant (1m) rise in sea level in the Charleston Coastline area at about 1100YBP was determined by coastline sediment features such as beach ridges, sand dunes and marsh-buried onshore trecs
' in roughly the same area defined by Talwani et al. as a graben. The authors state that they recognize a similar sea level rise at the same I time in southwest Florida. Although drawing no conclusions about the
[ cause, the implication was a eustatic rise or an epeirogenic (large scale [ downwarp of the coastline) event. It is rather coincidental, I thought, that they should recognize an abrupt short term sea level rise within the same general area that Colquhoun et al. recognize tectonic fluctuations of ! a graben.
- Jibson and Keefer studied slope stability and landsliding in the New Madrid seismic zone. They were able to identify many old slides showing block translations. Through field and historical dati, statistical analysis of distribution of large slides relative to 1.he New Madrid 1811-1812 epicenters, and site-specific seismic analysis, they were able to determine that young slides resulted from river bank undercutting and that, while slopes were presently stable, a critical ground acceleration of .179 would produce large scale landsliding in the study area.
- Schmoll et al.: An attempt at developing a methodology for seismic zonation in the Anchorage, Alaska, area focused on properties of the strata which are poorly known and the distribution of which is almost unknown. The presentation had little more information than the abstract, except for maps and a rough stratigraphic section. The idea is at an j early stage.
- McCarten and Gettings: Circular gravity and magnetic anomalies and subsurface structural features in the Southeast Georgia Embayment point to a mafic pluton 3 km thick, 10 km in diameter, 1.5 km below the surface of the Coastal Plain and bounded by faults. Upwarp of the "J" reflector i
offshore, subsurface sedimentary characteristics of late Tertiary sediments, and geothermal gradients suggest a late Tertiary age.of_20-30 million years before the present (MYBP). The pluton is located between Charleston and the Savannah River on the South Carolina Coast.
- Charlie et al.: An experimental attempt to understand conditions necessary to induce liquefaction involved both a laboratory compressional apparatus to simulate compressional waves and a finite-difference model.
The authors observed that ordinary explosives could produce sand boils and
^
geysers. In the lab, they measured the number of axial compressive stress pulses and the pore water pressure increases necessary to induce liquefaction using a compressive stress of 10,000 PSI, in sand. They found the sand liquefied at a .1% strain with peak particle velocity of 1 cm/sec, They ran several tests but did not vary the type of material. This will be done in future tests, t
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EB RESULTS OF RECENT SEISM 0 TECTONIC STUDIES IN ' DIE Ne 74081 ! CHARLESTON AREA TALWANI, Pradeep; COLQUHOUN, D.J. and LENNON, Gered, Geology , Department, University of South Carolina, Columbia, S.C. 29208. In order to understand the cause and nature of seismicity near These include Charleston we have examined an assortment of data. relocated hypocenters, potential field, seismic, shallow stratigraphic and releveling data, together with seismicity, releveling and paleo-seismicity data. An evaluation of these data suggest the following:
- 1. A NW trending graben, of which one flank is possibly related g to the buried (4-7 km) Ashley River f ault ( ARF) . '
- 2. The seismi. reflection and hypocentral data suggest that the ARF is cut by the NNE trending Woodstock f ault, which is downdropped -
to the NW.
- 3. The block defined by the Woodstock and ARF is postulated to represent the seismogenic feature responsible for seismicity. ,
4 The pattern of isoseismals of current felt earthquakes resembles the outline of the NW trending graben.
- 5. Historical and other data suggest that both sources were active in 1886.
- 6. The results of paleoseismological studies suggest a recurrent time of 1500-1700 Y. for similar events.
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l COMPARISON O NE0 TECTONIC DISTORTION WITH ISO- AND Eu- t43 79 STATIC SEA
'VELS IN HID - LATE HOLOCENE S0uTH CAROLINA COLQUOH N Donald J., TALWANI, Pradeep LENNON, Cered,POLEY, Kat -
and ROOKS, Mark, Geology Dept., Univ. of S.C., Columbia,SC 292 8 A_Il c oa s ines reflect isostatic, (ice or water loading and unloading), te_ctonigf (f olding and faulting) and neotectonic (migration of the geoid) pistortions through time. are ufque and no general curve exists.Thus Holocene ~ sea-level change curves Nevertheless eustatic changes j (true nent i changes in sea level itsell through ice / water ratios on conti-vol land masses, volume changes in ocean basins, specific gravity or e changes in amount of ocean water) exist, and can be observed and est mated. th They are probably related to global climatic changes within Holocene d tinant prior through the Oligocene, and to sea-floor spreading as well, to late Eocene. ( < eloped through marsh stratigraphic and archeologicOur sea level change cur indicators be-t 2een Georgetown and Savannah. coincidence in time of change iri NW rope was noted. Some of the s6a11er 11uctuations were thought eusta-EE. uetailed" studies (1983-85) ind South Edisto reveal rapid sea riseat Winyah Bay, Charleston and North 6000 B.P. (meters /1000 yrs) slowing near
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ontinuing to (cms the /100 yrs) with small fluctuations (amplitude uncertain) present.
- Tectonic distortion in our study area oc-l urs in a crnhen landward inged near Summerville. between Goose Creek ~and Kiawah Island and
- Sporadic movement began in the Thanetian and entinues through the 1970's with movement remaining similiar. In
.pite of this, archeologic indicators (thought to reflect custatic hanges) within and without c the graben express similiar clustering of e tes, as does timing of rapid to slow change. Thus these custatic ti ements generally exceed neotectonic, tectonic and isostatic distor-B.F , of this Coastal Plain, and prove eustatic rate change near -6000
, tuat (observed in the Pacific and elsewhere) and small eustatic fl uns both here, N.W. Europe, Richmond Gulf and elsewhere.
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. RRIER-ISLAND PROGRADATION AND THE 1100N2 BP 89 SEA-LEVEL EVENT STAPOR, Frank W., IN CENTRAL SOUTH CAROLINA Exxon Prod. Research Co., Box 2189, Houston , TX 77001; MATHEWS, Thomas D., MRRI, Box 12559, Charleston, SC 29412, and LINDSFORS-KEARNS, Fonda L.,
Survey, LSU Box G, Baton Rouge, LA 70893 Louisiana Geological Botany, Seabrook, Kiawah, and the Isle of Palms experienced significa seaward progradation during the period !!00-600 BP. ridges of Seabrook, Kiawah, and the Isle of Palms indicate direct onshore while the curved, spit-type ridges of Botany indicate littoral-transport .Seach locally with poorly developed dunes. Because quite similar to that of ridges formed over the past 50 years, sea lev their formation was at a position essentially equal to that of today. The marsh-buried beach ridges at Edisto Beach that were deposited about 1300 BP and the marsh-buried beach ridges at St. Phillips Island that contain 1000 BP pine stumps suggest a sea-level position somewhat lower than prese Thus, a much assignificant I m, thatrise in sea-level occurred at about initiation and/or progradationwas quickly followed, I4 within C-years, by the2u01100 B of Botany, Seabrook, and Kiawah. It is hypothesized that the adjustment of the nearshore necessitated by this rise was characterized by accelerated onshore- as wellequ of sand in this region.as littoral-transport, because the nearshore and s The onset of progradation resulting from this sea-level event can is dependent vary from island on the local rate at which sediment is supplied and this to island. rogradation has ceased and now In central South Carolina island-wide ir mediately adjacent to ebb-tidal deltas. growth occurs only in those portions and Florida.milar in magnitude has been identified by the authors in southw (
DSLIDES JIBSON, IN THE Randall W., NEW MADRID SEISMIC ZONE N* 79196 U.S. Geological Survey, Resto During KEEFER, David K. , U.S. Geological Survey, MenloVA 22092, and the New Madrid earthquakes of 1811-12, bluffs k, CA 94025 rdering the Mississippi scale landsliding. alluvial plain in the epicentral region unde ent large Between Cairo,111. and Memphis, Tenn., e mapped 221eroded, old, large (greater than 200 ft wide) landslides of three : (1) typ coherent and (3) young, fresh slumps that block slides and slumps; (2) old earth lows; and are the only landslides present along such bluffs. occur only along near-riv and Historical accounts and field evidence indicate that most old coherent that the slides and earth flows date to the 1811-12 earthquak 1 area occurs along only bluffs currently active,the bordering large-scale river. landsliding in th Statistical analyses indicate that the regional dis tribution of these young, near-river slumps unde relates rcu t ting. most strongly to slope steepness, a result of fluvial Analysis of old coherent slides and earth flows indicates slope height, that but landslide that proximitydistribution is most strongly affected by earthquakes also has a significant effect.to the hypotenters of the 1811-12 Slope-stability analyses of an old coherent slide and an earth flo selected as representative of the principal kinds of landslid s present indicate that both were stable in aseismic conditions e en 1 when water tables were at highest possible levels . Newmark displacement analysis shows that ground shaking thatsuch aHowev in 1811-12 would failere in both slides. cause large displacements leading to cata rophic; These results indicate that n large' (mbrthquakes landsliding in much of the study area is likel 5.0) earthquakes may also trigger landslides at so . Moderate locations. l
SEISM 0TECHNISTRATIGR APHIC CELLS: AN APPROACH TO THE ANALYSIS OF SUBSURFACE GEOLOGY AT ANCHORAGE, No _ 5814 ALASKA, FOR USE IN SEISMIC ZONATION STUDIES l SCHM0LL, Henry R., ODUM, Jack K., and ESPINOSA, Alvaro F., U.S. Geological Survey, Boy 25046, MS 972. Denver, CO 80225 Metropolitan Anchorage. Alaska, at the eastern margin of the upper Cook Inlet basin, is underlain by eastward-thinning sedimentary rock and surficial deposits of Cretaceous through Holocene age that overli a basement complex of metamorphic and (or) plutonic rocks of mainly Mesozoic age. Cook Inlet basin lies atop an active Beniof f zone and is subject to major earthquakes. Synthesis of lithologic, thickness, geotechnical, and shear-wave data is needed to achieve a realistic seismic-zonation program for the region. Present knowledge of the subsurface, based largely on borehole data of uneven distribution and quality, decreases exponentially with depth. Limited geologic and seismic cross-section data and knowledge of regional geology suggest a preliminary model useful for identifying data acquisition needs. The model is illustrated by the matrix shown below. The rows represent five numbered, wedge-shaped, subhorizontal stratigraphic units that comprise basement (1); shale (2); silt , clay , and sandstone (3); and older (4) and younger (5) Pleistocene glacial deposits including coarse (c) and fine (f) members that differ by age in character and distribution. The columns represent seven G F E D C B A lettered seismotechnistratigraphic cells 2.7 2.1 1.5 0.9 0.5 0.1 0.02 of different average thickness above E~~ 37 3T 3Tc Sc 3c-~ Sc basement, given in kilometers. Each cf 4f 4fc 4c 4c 4c 1 cell is variably narrow and relatively 3 3 3 3 1 long, and includes a unique combination 2 2 2 1 of elements that are segments of the 1 1 1 1 stratigraphic units.
t N! 71768 ss STRATIGJ PHIC AND GEOPHYSICAL EVIDENCE FOR S. C. A TERKARY INTRUSION NEAR BEAUFORT, E., - McCARTAN, Lucy, and GETTINGS, Mark Center',, National U. S. Geological Survey, N Reston, V A 22092 mafic is intrusion indicated about 10 km by strong in diameter positive gravity atand1.5 km, \ depth structural high in magnetic anomalies and a closedlimestone near Beaufort,S. C. overlying upper Eocene Sediments of Oligocene age northeast of Beaufort and of Miocene age to the west and southwest indicate
- hat the
" Beaufort high" divided the Southeast Georgia Embayment The into two sub-basins by late Oligocene time.
stratigraphic relations and elevated geothermal gradients suggest an ageof ofthe 20-30 Ma forhigh Beaufort the through intrusion. Maintenance time despite several marine incursions implies continued uplift, probably due to effects of the intrusion Intrusions withand Tertiary compressional warping. similar geophysical signatures are commonest in the 1 southeast but are also present elsewhere along the Seismic profiles across Atlantic continential margin. Crossroads deep corehole, the anomalies at the Clubhouse 60 km north of Beaufort , show a flat Jurassic reflector, are Jurassic or older. so the intrusive rocks there 175 km northeast of Beaufort, a seismic line/
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However, crossing one of the o f fsho re anomalies shows an Substantiat on intrusion doming up Cenozoic sediments. for the Beaufort pluton would of a Tertiary age significantly change the current models of the Tert ary Georgia Embaymen't'.
' tectonic history of the Southeast /
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INVESTIGATION OF COMPRESSIONAL WAVE-INDUCE 0 LI EFACTION I4- 72
- CHARLIE, W. A., Civil Engineering Dept., Colorado State Universi
( Ft. Collins, CO 80523; DOEHRING, 0.0., Earth Resources Dept.,
) Colorado State University, ft. Collins, CO 80523; VEYERA, G.E., g Civil Engineering Dept., Colorado State University, Ft. Collins, CO 80523 Although most effort has been directed toward the study of liquefaction resulting from seismically-induced shear waves, natural and man-induced compressional waves are also capable of liquefying saturated sediments.
The state-of-the-art for predicting suct phenomena is at best limited. Although some empirical scaling factors have been determined from field tests, theoretical approaches are almost non-existent and have not been verified by experimental testing. A reliable means of predicting compressional wave liquefaction potential should find applications in mining, geophysical surveying, construction and the military. We have taken two approaches, a laboratory physical model and a finite difference computer model. Both techniques allow for the use of a wide variety of materials and initiating forces and yield porewater pressure response. Our laboratory model consists of a compressed air cannon that propels a projectile into the sample. Transducers monitor strain and porewater pressure every fifty thousandths of a second for two seconds. The computer model is based on Newton's Second Law of Motion and couples a simple analytic locking model, to simulate the hysteretic behavior of the sediment skeleton, with a linear model to simulate the elastic behavior of the fluid. Our laboratory and computer models produce nearly identical results and both compare favorably with the reager empirical data available in the Rus iand European literature. THE ROLE Or ppef annov Au c a v,n ar. ,s r -- - - c .'. f
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SUBSIDENCE PROBLEMS RELATED TO THE DEVELOPMENT OF 64757 SILICICLASTIC KARST ON THE CITRONELLE FORMATION OF SOUTHWESTERN ALABAMA tversity ISPHORDING. Wayne C., Department of Geology and Geography, of South Alabama, Mobile, AL 36688 and FLOWERS, George C., Depart-ment of Geology, Tulane University, New Orleans, LA 70118 The irreversible transfonnation of kaolinite to gibbsite and the c n-comitant negative volume change associated with the reaction has re ul-ted in residential structural damage in Mobile, Alabama. Failure o the insurance company to honor damage resulting from a " sinkhole col-lapse clause" resulted in litigation. The main points of contention in the trial were: (1) were the small depressions in the owner's yard caused by dissolution of material, resulting in the formation of subter anean voids?, (2) does the language used in the policy, i.e. "We cover for damages caused by sinkhole collapse due to the dissolution of lime-stone or similar rock formations." mean that because the Citronelle Sand h a rock formation (and assuming point (1) can be proved) that the resident should recover for damage to his house? Evidence introduced for the plaintiff included 'X-ray diffractograms, SEM photographs and grain size analyses. A summary of literature on the development of karst in non-carbonate terranes was also produced (e.g., quartzite karst from Venezuela, volcanic karst in New Mexico and later-ite karst from Australia. X-ray diffractograms indicated that gibbsite was being formed in the vadose zone; SEM photograps clearly revealed the
- presence of euhedral gibbsite crystals on both quartz grains and kaolin-ite. Size analyses were offered to disprove the allegation that the subsidence was a piping effect caused solely by removal of the silt com-ponent. Mass-balance equations and chemical analyses of groundwater were used to demonstrate th3t not only was kaolinite altering to gibben site, causing loss of volume, but that some quartz was also being t in into solution. Af ter consideration of the evidence, the jury four favor of the plaintiff and the resident was compensated for dam ,e.
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. POST PLIOCENE DISPLACEMENT ON FAULTS WlD11N DIE KENRICK1 - 440 RIVER FAULT ZONE OF EAST-CENTRAL. KENRICKY VanAradale, Roy B., Ceology Department, University of Arkansa .
Fayetteville, AR 72701 and Sergeant, Richard E., Kentucky Ce - logical Survey, Lexington, KY 40506 Numerous f aults of the Kentucky River f ault zone are partially overla kn - by Pliocene-Pleistocene terraces along the Kentucky river in east-central Kentucky. Preliminary drilling and electrical resistivity surveys suggest that a number of the f aults have been active since the deposition of the terraces. From these preliminary surveys 4 sites were selected and 9 trenches were excavated. Of these 9 trenches, 4 revealed f aulted and/or f olded terrace sediments. One trench was excavated across a N40W trending fault in southern Clark County, cutting 3m deep into a 10m thick terrace. A monoclinal flexure, clay dikes, an asymmetric anticline, and a thrust f ault which of f set a soil ped all were exposed in the trench wall. A second trench across this f ault revealed a reverse f ault which displaced the bedrock and the overlying terrace sediments by im. The third trench was excavated across a N60E trending fault in northern Madison County, exposing folded and f aulted Lexington Limestone, overlain by alluvium-colluvium. A line of charcoal f ragments, a line of barite nodules, and an underlying clay horizon in the alluvial-colluvial section appear to have locally folded with the underlying bedrock. Nearby, a fourth trench was excavated across another N60E trending fault revealing terrace folding and apparent f aulting with im of reverse displacement. Comparison of the 9 trenches indicates that the folding and fault ing of the terrace deposits is tectonic in origin and that the Kentu y River f ault zone has been active within the last 5 million years a probably within the last one million years. Recognition of relat cly young f ulting in Kentucky suggests that other mid-continent fa ts should b studied for recent displacement. EXPERIMENTAL SEJDY OF BONIN m N? 62917 , VAN DER LAAN, Sieger R. , FLOKER, hurtin F.J. , af Nataa8 eat c : --~-
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( I l N l 7615 ASSESSKNT OF THE STATE OF STRESS IN THE AT1. ANT!C COAST REGION No 64272
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ZOMCX, Mary Lou. U.S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA 94025, 70BACK, Mark D., Dept. of Geophysics, i . Stanford Univ. , Stanford, CA 94305, DART, Richard, U.S. Geological Survey, DFC, Denver, CO 80225 ! alqua : the Results of previous studies have suggested that a zone of NW-oriented turel compression exists along the Atlantic seaboard of the U.S. in contrast ; )th3. to the NE-to ENE-oriented maximum horizontal stresses found throughout ! i cod much of the midcontinent of North Anerica. Poorly constrained o of earthquake focal mechanisms and late Tertiary offsets across reverse ; nova (?) faults were the primary evidence for this conclusion. New stress i data, however, cast serious doubt on the existexe of a distinct o in nitu Atlantic coast stress province and suggest that the stress state characterizing the midcontinent region may be cantinuous into the vill midplate rygfon of the western north Atlantic. These new data ioty include: 1) analysis of borehole elongations (* breakouts") from d2:p exploration wells on the U.S. continental shelf which indicate a illow tha compressive stress orien}ation of approximately E-W in the Georges bank cnd area (6 well s), N 55*-70 E in the Baltimore Ca tyon field (13 wells), and N 40' E in the southeast Georgia embayment (1 well); 2) borehole ! icci elongation analysis of about 20 wells in southeastern Canada and on the avsy Scotian shelf indicating a N 50*-55* E compressive stress orientation l smic (Plumb and Cox,1984 EOS, p.1081-1082); 3) better-cons trained ) earthquake focal mechanisms obtained recently (Statton and others 1982, Eq. Notes, v. 53, p. 36; Talwani,1982, GEOLOGY, v.10, p. 654-658) and i a re-analysis, including error assessment, of previous focal mechanisms i in the New York-New Jersey area (Quittmeyer and others 1985, Eq. Notes, 1 in press); and 4) hydraulic fracture measurements and borehole j elongations in,a 1 km deep well near the Ramapo fault in NY which suggest a N 55 E + 10 maximum horizontal compressive stress
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