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Articles 1951 - 1980 of 2470

Full-Text Articles in Earth Sciences

Simulating A Large Wasatch Front, Utah, Earthquake Using Small Earthquake Recordings As Green's Functions, United States Department Of Defense, Air Force Geophysics Laboratory May 1986

Simulating A Large Wasatch Front, Utah, Earthquake Using Small Earthquake Recordings As Green's Functions, United States Department Of Defense, Air Force Geophysics Laboratory

Geology

Several earthquake recordings at Golden, Colorado in the magnitude range 4-6, were digitized and were used to investigate the feasibility of adding them together to simulate a larger earthquake (magnitude 7.0-7.5). The test path of the Wasatch Front, Utah to the WWSSN station at Golden was selected (distance=400-500 km). The hypothetical causative fault was given dimensions on the order of 45 km long by 20 km wide and was divided into "cells," representative in size to the "seed" events rupture dimensions and with other variations. The results were evaluated by total energy and amplitude criteria. The final waveforms were judged …


Transient Electromagnetic Sounding For Groundwater, David V. Fitterman, Mark T. Stewart Apr 1986

Transient Electromagnetic Sounding For Groundwater, David V. Fitterman, Mark T. Stewart

Geology Faculty Publications

The feasibility of using the transient electromagnetic sounding (TS or TDEM) method for groundwater exploration can be studied by means of numerical models. As examples of its applicability to groundwater exploration, we study four groundwater exploration problems: (1) mapping of alluvial fill and gravel zones over bedrock; (2) mapping of sand and gravel lenses in till; (3) detection of salt or brackish water interfaces in freshwater aquifers; and (4) determination of hydrostratigraphy. These groundwater problems require determination of the depth to bedrock; location of resistive, high-porosity zones associated with fresh water; determination of formation resistivity to assess water quality; and …


The Physics Of The Antarctic Circumpolar Current, Worth D. Nowlin, John M. Klinck Jan 1986

The Physics Of The Antarctic Circumpolar Current, Worth D. Nowlin, John M. Klinck

CCPO Publications

A region of transition of surface water characteristics from subantarctic to Antarctic and an associated eastward flowing Antarctic Circumpolar Current (ACC) have long been recognized to exist as a band around Antarctica. In this review we summarize the most important observational and theoretical findings of the past decade regarding the ACC, identify gaps in our knowledge, and recommend studies to address these. The nature of the meridional zonation of the ACC is only now being revealed. The ACC seems to exist as multiple narrow jets imbedded in, or associated with, density fronts (the Subantarctic and Polar fronts) which appear to …


On The Linear Relation Between Mb And Ms For Discrimination Between Explosions And Earthquakes, Ali A. Nowroozi Jan 1986

On The Linear Relation Between Mb And Ms For Discrimination Between Explosions And Earthquakes, Ali A. Nowroozi

OES Faculty Publications

Summary. The statistical capability of the mb :Ms, discriminant for the discrimination of earthquake and explosion populations is examined by application of discriminant functions to a group of 83 explosions and 72 earthquakes in Eurasia. Equations are derived for the probability that an event is an earthquake or an explosion. The positive sign of DIS in the decision index equation,

DIS, = 34.3383 - 11.9569 mbi, + 7.1 161 Msi,

indicates that the event i is an earthquake. Its negative sign indicates that event i is an explosion. The probability of …


Geology Of The Escalante District, Iron County, Utah, James William Biehl Jan 1986

Geology Of The Escalante District, Iron County, Utah, James William Biehl

Masters Theses

"The Escalante Silver District, Iron County, Utah, occupies a group of low hills extending to the Escalante Desert from the Black Hills to the south. Tertiary volcanics serve as host rocks for silver bearing quartz veins. Five map units, with a total of 12 members are recognized. X-ray fluorescence and field mapping enabled differentiation of the units, while thin section analysis enabled characterization of the members. The map units formed in three episodes. The oldest is extrusive doming of distinctive older lava and breccia flows. The middle group is made up of tectontic breccias, sillar-like lava flows, and volcaniclastic sediments …


The Use Of Electrical Resistivity To Delineate A Brine Contamination Plume In The Walker Oilfield, Kent County, Michigan, Kent E. Meisel Dec 1985

The Use Of Electrical Resistivity To Delineate A Brine Contamination Plume In The Walker Oilfield, Kent County, Michigan, Kent E. Meisel

Masters Theses

Contamination of groundwater with oil field brines was reported in the Walker Oil Field, Michigan. An electrical resistivity survey utilizing the Vertical Electrical Sounding method was conducted to test the method as an exploratory tool for delineating brine contamination in glacial deposits. The method was successful in defining the subsurface geology and delineating a shallow, confined aquifer, but the presence of extensive, conductive clays effectively masked the presence of brine contamination. The method was shown to be an effective exploratory tool for shallow investigations.


A Geophysical Model Of The Gravity-Magnetic High, Virginia Coastal Plan, Gordon Everett Davison Apr 1985

A Geophysical Model Of The Gravity-Magnetic High, Virginia Coastal Plan, Gordon Everett Davison

OES Theses and Dissertations

The coastal plain province of Virginia is characterized by a coincidental gravity and magnetic high separating Appalachian-trend geophysical signatures to the west from non-Appalachian signatures to the east. Two cross-trend gravity and magnetic profiles, one on the Northern Neck of Virginia and one along Interstate Highway 64, were used to interpret the anomalous high. The profile models suggests that the anomaly is characterized by high-density, variably magnetic, east-dipping (60°) crustal blocks. Further information from well-logs indicate that the anomaly is due to meta-mafic rocks of oceanic origin, flanked by low-density, lower susceptibility, granitic units. This suggests that the anomalous gravity-magnetic …


Carbonate Facies Of The Kimmswick Limestone (Trenton/Galena) In Southwestern Illinois : Their Relations As Oil Reservoirs And Traps, Gregory A. Crews Jan 1985

Carbonate Facies Of The Kimmswick Limestone (Trenton/Galena) In Southwestern Illinois : Their Relations As Oil Reservoirs And Traps, Gregory A. Crews

Masters Theses

"Four potentially productive oil horizons have been identified in the Kimmswick Limestone (Trenton/Galena), Ordovician of southwestern Illinois. Four non-porous caprock zones and four porous horizons were identified and informally named after corresponding members of the Dunleith Formation (Illinois State Geological Survey classification). The porous horizons generally consist of coarse-grained, fossiliferous limestone, which is overlain by finer grained, spar-cemented, impermeable limestone.

In order of production potential, the horizons are the upper Moredock, lower Moredock, Beecher-St. James (lowermost stratigraphic unit), and New London (uppermost stratigraphic unit). Porosity in the upper Moredock horizon is relatively consistent throughout the study area, as determined by …


Fault Movements And Tectonics Of Eastern Iran: Boundaries Of The Lut Plate, Ali A. Nowroozi, A. Mohajer-Ashjai Jan 1985

Fault Movements And Tectonics Of Eastern Iran: Boundaries Of The Lut Plate, Ali A. Nowroozi, A. Mohajer-Ashjai

OES Faculty Publications

Summary. From 1977 March 21 to 1981 July 28, about 15 earthquakes with Ms ≥6.0 and many earthquakes with Ms≥4.5 have occurred in Iran. The upsurge of seismic activity started following the Khorqu earthquake of 1977 March 21, M,=7.0, south-east of the Fars folded series of Zagros. This shock had a thrust focal mechanism solution indicating the general northward movement of the Arabian plate with respect to the Iranian landmass. It was followed by six major damaging earthquakes in eastern Iran. The earthquakes are associated with extensive faulting which surrounds the Lut plate. (1) The Zarand earthquake …


Tectonic Implications Of Late Tertiary Strata Exposed Along The Piankatank River, Eastern Virginia, Daniel Stephen Lane Oct 1984

Tectonic Implications Of Late Tertiary Strata Exposed Along The Piankatank River, Eastern Virginia, Daniel Stephen Lane

OES Theses and Dissertations

Biostratigraphic analysis of Late Miocene and Pliocene strata along the Piankatank River in eastern Virginia exposes a juxtaposition of the Eastover and Yorktown Formations. This structure is situated on a NE trending alignment of geological, geomorphic, and geophysical features which run from southern Virginia to northern Delaware. Tectonic jointing in isolated sandstone bodies and fracture controlled drainage patterns provide further evidence of post-middle Pliocene tectonism in the region. The lateral spacing of this structure from the Stafford and Brandywine fault zones and other linear features on the Coastal Plain strongly implies that a structural similarity exists between the Piankatank structure …


Land Use Effects On Shallow Earth Resistivity, Gary James Barton Aug 1984

Land Use Effects On Shallow Earth Resistivity, Gary James Barton

Masters Theses

No abstract provided.


A High-Resolution Bathymetry Map For The Marguerite Bay And Adjacent West Antarctic Peninsula Shelf For The Southern Ocean Globec Program, S. T. Bolmer, R. C. Beardsley, C. Pudsey, P. Morris, P. Wiebe, Eileen E. Hofmann, J. Anderson, A. Maldonado May 1984

A High-Resolution Bathymetry Map For The Marguerite Bay And Adjacent West Antarctic Peninsula Shelf For The Southern Ocean Globec Program, S. T. Bolmer, R. C. Beardsley, C. Pudsey, P. Morris, P. Wiebe, Eileen E. Hofmann, J. Anderson, A. Maldonado

OES Faculty Publications

One objective of the U.S. Southern Ocean Global Ocean Ecosystems Dynamics (SO GLOBEC) program is to gain a better understanding of the sea floor bathymetry in the program study area. Much of Marguerite Bay and the adjacent shelf west of the Antarctic Peninsula were poorly charted when the SO GLOBEC program started in 2000. Before the first SO GLOBEC cruise, an improved local area version (ETOPO8.2A) was created from the Smith and Sandwell (1997) topo_8.2.img 2-minute digital gridded bathymetry for the study area. The first SO GLOBEC mooring cruise on the R/V Lawrence M. Gould (March 2001) showed that the …


A Geophysical Investigation Of A Possible Astrobleme In Southwestern Michigan, Suhas L. Ghatge Apr 1984

A Geophysical Investigation Of A Possible Astrobleme In Southwestern Michigan, Suhas L. Ghatge

Masters Theses

A circular pattern to the oil production in Calvin Township, Cass County, Michigan, absence of about 1200 feet of Ordovician sediments and uplift indicated by a deep drill hole in the center of the productive area and absence of anomalies on the regional gravity and magnetic maps led to detailed gravity and magnetic surveys over this structure to delineate it and provide information regarding its genesis.

The Bouguer gravity and magnetic anomaly maps show no anomaly associated with the structure. The 28-mile wavelength second harmonic residual gravity and magnetic maps show linear features in the area. Two dimensional gravity modeling …


Lithology And Sedimentology Of The Graydon Springs Channel, Pennsylvanian Of Southwestern Missouri, Gregory Lee Easson Jan 1984

Lithology And Sedimentology Of The Graydon Springs Channel, Pennsylvanian Of Southwestern Missouri, Gregory Lee Easson

Masters Theses

"The Graydon Springs Member of Southwest Missouri, here assigned to the Warner Formation of Pennsylvanian age was sampled and examined in order to document the lithology, sedimentology, source area, stratigraphic position, and overall geologic history of these channel-like bodies. The member is composed of an upper sandstone unit and a lower conglomerate unit.

Laboratory investigations of thin sections indicate that the sandstone unit is composed of well sorted, well rounded quartz and minor amounts of accessory minerals cemented with iron oxide, commonly hematite. Field observations indicate that the conglomerate unit is composed of very poorly sorted, very well rounded chert …


Relation Of Bitumen To Ore In The Magmont West Orebody, Southeast Missouri, Mark Alan Marikos Jan 1984

Relation Of Bitumen To Ore In The Magmont West Orebody, Southeast Missouri, Mark Alan Marikos

Masters Theses

"Bitumen in the form of oil blebs from the Magmont West orebody of the Viburnum Trend was examined and analysed in an attempt to relate hydrocarbon distribution and origin to ore genesis. Hydrogen, carbon, nitrogen, sulfur and oxygen percentages were determined by elemental analyses. Trace element composition was determined by emmission spectroscopy and the composition of the bitumen was calculated with respect to aromatic hydrocarbons, saturated hydrocarbons and NSO (nitrogen-sulfur-oxygen) components. The bitumen and kerogen from associated shale samples were evaluated by Rock-Eval pyrolysis and pyrolysis-gas chromatography.

The bitumen was calculated to be approximately 40 to 50 percent aromatic and …


Oil Producing Upper Cherokee And Lower Marmaton (Pennsylvanian) Channel Sandstones Of Jackson And Cass Counties, Missouri, Stephen Thomas Carroll Jan 1984

Oil Producing Upper Cherokee And Lower Marmaton (Pennsylvanian) Channel Sandstones Of Jackson And Cass Counties, Missouri, Stephen Thomas Carroll

Masters Theses

"Approximately 240 gamma ray-neutron logs were interpreted and correlated in an attempt to isolate separate channels collectively referred to as "Squirrel" sands in the upper Cherokee and lower Marmaton (Pennsylvanian) rocks of Jackson and Cass counties, Missouri. Isopach maps were prepared for two of the identifiable fluvial sandstones and a structure map was drawn on the laterally extensive Anna Shale.

The term "Squirrel" has been applied to as many as five different sandstone packages, and thus, has been the source of a great deal of confusion. In an attempt to sort out the confusion this thesis recognizes and defines three …


A Magnetic And Resistivity Survey Of Cork Street Landfill, Stanislaw Leja Dec 1983

A Magnetic And Resistivity Survey Of Cork Street Landfill, Stanislaw Leja

Masters Theses

Geophysical techniques such as magnetic and electrical resistivity methods are being increasingly applied in investigations of landfills.

For this survey, measurements of the intensity of the earth's magnetic field were taken at regular intervals along traverses. Resistivity readings were taken at selected intervals along the same or very similar traverses. Additional resistivity depth measurements or soundings were obtained at selected points in and around the landfill.

Profiles were analyzed for individual dump structures and for overall magnetic and resistivity response. Contour maps were drawn from the measurements at the site to depict broad trends or patterns. Deeper subsurface geology was …


Geophysical Strain And Tilt: Measurement Methodology And Analysis Of Data, Robert Mackay Aug 1983

Geophysical Strain And Tilt: Measurement Methodology And Analysis Of Data, Robert Mackay

Dissertations and Theses

Tilt and strain meters were installed on the Portland State University campus in the summer of 1982 and data was collected for 4 months. Instrument selection, operation, installation and performance are discussed.

Suggestions that could enhance data quality and data collection efficiency are presented.

An analysis procedure is suggested and an example of this procedure for an interval of data is discussed. The influence of the temperature, pressure, rainfall and solid earth tides on the signal is investigated, as well as the correlation between similar channels of the different tilt instruments. The temperature, rainfall and solid earth tides were all …


A Comparative Study Of Geologic Information Derived From Visually Interpreted Slar And Landsat Imagery, William Leo Barry Aug 1983

A Comparative Study Of Geologic Information Derived From Visually Interpreted Slar And Landsat Imagery, William Leo Barry

All-Inclusive List of Electronic Theses and Dissertations

Geologists have used numerous tYPes of remote sensors for the interpretation of earth surface features. Two of the more recently developed remote sensors are SLAR (side-looking airborne radar) and LANDSAT (ERTS, Earth's Resources Technology Satellite, renamed L~~DSAT). The author undertook a straightforward qualitative research study to ascertain and compare the amount, types and reliability of the geologic information which can be derived separately from visually interpreted LANDSAT and SLAR imagery. The area selected for this study is located in north-central Arizona. The imagery analyzed consists of unenhanced black and white ... multispectral scanner (MSS) bands 5, 6 and 7 LANDSAT …


A High Resolution Ground Magnetic Study Of Part Of The Albion-Scipio Trend, Steven James Hoin Aug 1983

A High Resolution Ground Magnetic Study Of Part Of The Albion-Scipio Trend, Steven James Hoin

Masters Theses

A detailed high resolution ground magnetic survey was conducted over part of the Albion-Scipio Oil Field Trend. The purpose of the survey was to delineate any magnetic anomalies associated with the trend. A field method using two magnetometers was employed. Sixteen simultaneous readings were taken at a mobile and a base station, and the field operator read the total field values using a 'T ', or similar pattern. This method eliminated much of the noise associated with ground surveys. The resulting residual magnetic map indicates that the basement rocks consist of mafic and felsic, dikes and plutons. Several discontinuities are …


Design, Construction, And Testing Of A Microprocessor-Controlled Interface Between Analog Geophysical Equipment And A Digital Cassette Recorder, Mohd. Nawawi Mohd. Nordin Aug 1983

Design, Construction, And Testing Of A Microprocessor-Controlled Interface Between Analog Geophysical Equipment And A Digital Cassette Recorder, Mohd. Nawawi Mohd. Nordin

Masters Theses

A Digital Data Acquisition System (DDAS) microcomputer was designed and constructed to interface between a six-channel analog seismograph and a digital cassette recorder. The DDAS microcomputer is a relatively inexpensive microcomputer built around the popular Z-80 microprocessor chip. It is portable and has 26K bytes of memory. It was designed to convert analog data in to digital with some processing performed before storing on the digital cassette recorder, for later analysis. The same hardware or circuitry of the DDAS microcomputer can perform other functions and work with other geophysical equipment by changing the software of the microcomputer.


The Geology Of Maine's Coastline : A Handbook For Resource Planners, Developers, And Managers, Maine State Planning Office Jun 1983

The Geology Of Maine's Coastline : A Handbook For Resource Planners, Developers, And Managers, Maine State Planning Office

Maine Collection

The Geology of Maine's Coastline : A Handbook for Resource Planners, Developers, and Managers

Executive Department, Maine State Planning Office, Augusta, Maine, June 1983.

Contents: List of Figures / Introduction: The Geological Connection / Chapter 1: Using the Marine Environments Maps / Chapter 2: Perspectives of the Maine Coast / Chapter 3: The Building Blocks of Maine's Coast / Chapter 4: The Disappearing Shoreline / Where to Go for Help / Some Planning Considerations for Development in Coastal Geologic Environments / Land Use Laws of Special Interest to Individual Coastal Property Owners


Electrical Resistivity Survey Near The "Kl" Avenue Landfill, Kalamazoo County, Michigan, David W. Hall Apr 1983

Electrical Resistivity Survey Near The "Kl" Avenue Landfill, Kalamazoo County, Michigan, David W. Hall

Masters Theses

The KL Avenue Landfill near Kalamazoo, Michigan has recently become an area of ground water contamination. As of April, 1979, the landfill was closed due to contaminated wells to the west. This area was chosen to study because preliminary electrical resistivity surveys indicated that the approximate areal extent and depth of the contamination may be located without the additional cost of drilling wells. It is the intent of this study to use the Schlumberger Vertical Electrical Sounding method to construct a hydrogeologic model for this area.

This study is a rather critical test of the Schlumberger VES method in a …


Chronology Of Late Pleistocene And Holocene Volcanics, Long Valley And Mono Basin Geothermal Areas, Eastern California, Spencer H. Wood Jan 1983

Chronology Of Late Pleistocene And Holocene Volcanics, Long Valley And Mono Basin Geothermal Areas, Eastern California, Spencer H. Wood

Geosciences Faculty Publications and Presentations

Hydration-rind ages based on hydration-rind thicknesses of obsidian and an assumed hydration rate of 5 microns2/1000 yrs have been determined for the 26 exposed Mono domes and coulees. Hydration-rind thickness data give good estimates of relative age differences between the domes, but determination of absolute ages will depend upon calibration to radiometric ages.

The first extrusion of highly differentiated, sparsely porphyritic rhyolite occurred an estimated 32,000 to 40,000 yrs ago and consists of a small dome at the northwest end of the contiguous chain. The next major extrusive event occurred about 24,000 yrs ago and is represented by …


Geochemistry And Petrology Of The Cold Springs Breccia Formation, Wichita Mountains, Oklahoma, Dana Marie Vidrine Jan 1983

Geochemistry And Petrology Of The Cold Springs Breccia Formation, Wichita Mountains, Oklahoma, Dana Marie Vidrine

Masters Theses

"In the Wichita province of southwestern Oklahoma the Cold Springs Breccia Formation, exposed in a 15 km2 area in Kiowa County, is characterized by blocks and pillows of microdiorite surrounded by pink granite. Intimately associated with this mixed zone are sill-like bodies of intermediate rocks, granodiorites and tonalites. The intermediate rocks have been interpreted as hybrids produced by assimilation of microdiorite by granitic magma, and the mixed zone has been interpreted as an intrusion breccia formed at the margins of the hybrid sills.

Major, minor and trace element data have been obtained on a suite of granites, intermediates, and …


Lithofacies Analysis Of The Roubidoux Formation, South Central Missouri, Michael William Harbaugh Jan 1983

Lithofacies Analysis Of The Roubidoux Formation, South Central Missouri, Michael William Harbaugh

Masters Theses

"Lithologic and thickness data of the Lower Ordovician rocks of the Roubidoux Formation, south central Missouri, were interpreted from sample logs. Maps included are based on structure, thickness and lateral and vertical lithologic variability. Sand distribution in the Roubidoux is represented by a "sand percentage" map, a "sand isolith" map, and a "tripartite sand distribution" map. The Roubidoux Formation consists of a sequence of dolomite, sandy dolomite, sand and chert. It is believed that the Roubidoux was deposited on a stable marine platform receiving a supply of elastics from the north and northeast. The sands were deposited by longshore or …


The Precambrian Volcanic Stratigraphy And Petrology Of The Des Arc Ne 7 1/2 Minute Quadrangle, South Central St. Francois Mountains, Missouri, Vernon Max Brown Jan 1983

The Precambrian Volcanic Stratigraphy And Petrology Of The Des Arc Ne 7 1/2 Minute Quadrangle, South Central St. Francois Mountains, Missouri, Vernon Max Brown

Doctoral Dissertations

"The Precambrian volcanics in the Des Arc NE 7½ minute quadrangle are composed predominantly of rhyolitic ash-flow tuffs with minor rhyolitic, trachytic, and andesitic lavas, and basaltic dikes. Thirty-seven volcanic units were identified, mapped, and informally named. A minimum of 1,000 meters of volcanic section is present. The rhyolites consist of phenocrysts of albitized alkali feldspar, albitic plagioclase, quartz, opaques, and ferromagnesium relicts set in a devitrified and locally recrystallized felsitic matrix. Pumice and lithophysal structures are common in the ash flows.

Chemically, the rhyolites are quite similar. The potassium to sodium ratio in individual units, however, tends to vary …


Lead-Zinc Metallotects Of The Ozark Dome, Linda Leigh Mallery Jan 1983

Lead-Zinc Metallotects Of The Ozark Dome, Linda Leigh Mallery

Masters Theses

"This is a regional study of the relationship between Mississippi Valley-type mineral deposits and structural features of the Ozark dome which resulted in the description and classification of lead-zinc "metallotects". A more accurate delineation of the Ozark dome was accomplished by examining the gradient and structural contour lines of its Precambrian basement. A general background on the geology, structure, and evaluation of the Ozark dome was discussed along with the stratigraphy, structure, and ore deposits of the major lead-zinc districts of the Ozark dome in order to develop the background data for the application of the "metallotect" concept. The major …


Basement Rocks Of The Main Interior Basins Of The Midcontinent, Edward C. Lidiak Dec 1982

Basement Rocks Of The Main Interior Basins Of The Midcontinent, Edward C. Lidiak

UMR Journal -- V. H. McNutt Colloquium Series

The basement underlying the deeper basins in the Midcontinent is not well known because of the considerable thickness of overlying sedimentary rocks. However, gravity and magnetic surveys and sparse wells to basement suggest that deeper intracratonic basins are characteristically underlain by denser and more magnetic rocks than in adjacent areas. This correlation has important bearing on understanding the tectonic development and geologic history of Midcontinent basins.

The Michigan basin is underlain by prominent, linear gravity and magnetic highs that extend across the southern peninsula. A recent deep well to basement encountered basalt overlain by red clastic sedimentary rock. The combined …


Structure Of The Salina-Forest City Interbasin Boundary From Seismic Studies, Don W. Steeples Dec 1982

Structure Of The Salina-Forest City Interbasin Boundary From Seismic Studies, Don W. Steeples

UMR Journal -- V. H. McNutt Colloquium Series

As petroleum exploration efforts in the Midcontinent become directed toward smaller fields and the search for minerals is extended into new areas, the edges of the Salina and Forest City basins will become of increased interest to industry. The principal boundary feature between the two basins is the Nemaha ridge, a linear feature that extends from near Omaha, Nebraska, to near Oklahoma City, Oklahoma. Recent seismic studies at the Kansas Geological Survey have revealed a complex array of faulted and folded structures in the vicinity of the Humboldt fault zone (the eastern flank of the Nemaha ridge). Faulting of both …