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At least 1,711 records · Page 95Linked to original sources
USGS2023

System characterization report on the BlackSky Global multispectral sensor

Executive Summary This report addresses system characterization of the BlackSky Global satellites and is part of a series of system characterization reports produced and delivered by the U.S. Geological Survey Earth Resources Observation and Science Cal/Val Center of Excellence. These reports present and detail the methodology and procedures for characterization; present technical and operational information about the specific sensing system being evaluated; and provide a summary of test measurements, data retention practices, data analysis results, and conclusions. The BlackSky Global satellites are three-band multispectral imagers (red, green, and blue multispectral bands plus a panchromatic band) with a 0.8- to 0.9-meter (m) pixel ground sample distance for the assessed satellites. BlackSky Global satellites 9 and 12–17 were launched in March and December 2021, respectively, into a Sun-synchronous orbit of 430–450 kilometers with an inclination of 42–53 degrees and a swath width of 6 kilometers at nadir. Each Global satellite has an expected lifetime of about 3 years. More information on the BlackSky Global satellites is available in the “Land Remote Sensing Satellites Online Compendium” ( https://calval.cr.usgs.gov/apps/compendium ) and from BlackSky at Real-Time Space-Based Intelligence (blacksky.com) The Earth Resources Observation and Science Cal/Val Center of Excellence system characterization team completed data analyses to characterize the geometric (interior and exterior) and spatial performances. Results of these analyses indicate that the assessed BlackSky Global satellites have an interior geometric performance in the range of −0.011 m (−0.012 pixel) to 0.007 m (0.008 pixel) in easting and −0.018 m (−0.020 pixel) to 0.012 m (0.013 pixel) in northing in band-to-band registration; an exterior geometric performance using ground control points of 8.0-m circular error (95-percent certainty) for orthorectified products and 10.7- to 17.4-m circular error (95-percent certainty) for nonorthorectified products, depending on the geolocation metadata used; and a spatial performance in the range of 1.70 to 2.43 pixels for full width at half maximum, with a modulation transfer function at a Nyquist frequency in the range of 0.032 to 0.084.

Open-File Report↗
USGS2025

System characterization report on the Environmental Mapping and Analysis Program (EnMAP)

This report addresses system characterization of the Environmental Mapping and Analysis Program hyperspectral sensor by the DLR (German Aerospace Center, ground segment project management), GFZ (Deutsches Geoforschungszentrum, science lead) and is part of a series of system characterization reports produced and delivered by the U.S. Geological Survey Earth Resources Observation and Science Cal/Val Center of Excellence. These reports present and detail the methodology and procedures for characterization; present technical and operational information about the EnMAP hyperspectral sensor; and provide a summary of test measurements, data retention practices, data analysis results, and conclusions. The Earth Resources Observation and Science Cal/Val Center of Excellence system characterization team completed data analyses to characterize the geometric (interior and exterior), and radiometric performances of the EnMAP hyperspectral sensor. Results of these analyses indicate that the Environmental Mapping and Analysis Program has a band-to-band geometric performance in the range of −0.135 to 0.15 pixel, geometric performance relative to the Operational Land Imager in the range of −27.716 meters (−0.92 pixel) to 32.892 meters (1.09 pixels) offset in comparison to Landsat 8 Operational Land Imager, offset of a radiometric comparison in the range of −0.012 to 0.020, slope of a radiometric comparison in the range of 0.947 to 1.031.

Open-File Report↗
USGS2025

System characterization report on Resourcesat-2A Linear Imaging Self Scanning-3 sensor

Executive Summary This report addresses system characterization of the Indian Space Research Organisation Resourcesat-2A Linear Imaging Self Scanning-3 sensor and is part of a series of system characterization reports produced and delivered by the U.S. Geological Survey Earth Resources Observation and Science Cal/Val Center of Excellence since 2021. These reports present and detail the methodology and procedures for characterization, present technical and operational information about the specific sensing system being evaluated, and provide a summary of test measurements, data retention practices, data analysis results, and conclusions. Resourcesat-2A is identical to Resourcesat-2 and was launched in 2016 on the Polar Satellite Launch Vehicle-C36 for continuity of data and improved temporal resolution. The Resourcesat-2 platform (which includes Resourcesat-2A) is of Indian Remote Sensing Satellites-1C/1D–P3 heritage and was built by the Indian Space Research Organisation. Resourcesat-2 and Resourcesat-2A carry the Linear Imaging Self Scanning-3 and Linear Imaging Self Scanning-4 sensors for medium-resolution imaging. More information on Indian Space Research Organisation satellites and sensors is available in the “2022 Joint Agency Commercial Imagery Evaluation—Remote Sensing Satellite Compendium” and from the manufacturer at https://www.isro.gov.in/ . The Earth Resources Observation and Science Cal/Val Center of Excellence system characterization team completed data analyses to characterize the geometric (interior and exterior), radiometric, and spatial performances. To summarize the results, we have determined that this sensor provides an interior geometric performance with mean offsets in the range of 1.75 meters (m; 0.06 pixel) to 6.83 m (0.23 pixel) in easting and −1.83 m (−0.06 pixel) to 1.81 m (0.06 pixel) in northing in band-to-band registration and a root mean square error in the range of 3.81 m (0.13 pixel) to 8.19 m (0.27 pixel) in easting and 2.21 m (0.09 pixel) to 4.72 m (0.16 pixel) in northing. We have measured an exterior geometric error offset in the range of −21.29 to 6.88 m in easting and −7.35 to −2.63 m in northing, and the root mean square error is in the range of 7.19 to 21.43 m in easting and 3.64 to 8.19 m in northing in comparison to the Landsat 8 Operational Land Imager. The measured radiometric performance was in the range of −0.002 to 0.031 in offset and 0.701 to 0.940 in slope, and the spatial performance was in the range of 1.204 to 1.265 pixels for full width at half maximum with a modulation transfer function at a Nyquist frequency in the range of 0.251 to 0.277.

Open-File Report↗
USGS2026

System characterization report on Tanager

Executive Summary This report addresses the system characterization of the Tanager satellite hyperspectral sensor created by Planet Labs PBC and is part of a series of system characterization reports produced and delivered by the U.S. Geological Survey Earth Resources Observation and Science Cal/Val Center of Excellence. These reports present and detail the methodology and procedures for characterization; present technical and operational information about the Tanager hyperspectral sensor; and provide a summary of test measurements, data retention practices, data analysis results, and conclusions. This report summarizes the sensor performance of the Tanager based on the U.S. Geological Survey Earth Resources Observation and Science Cal/Val Center of Excellence system characterization process. In summary, we determined that the Tanager exhibits a band- to- band geometric error ranging from −0.074 to 0.097 pixel. Compared to the Landsat Operational Land Imager, geometric offsets ranged from −5.980 meters (−0.20 pixel) to 11.348 meters (0.40 pixel). Radiometric comparisons showed offsets between −0.004 and 0.056 with slopes from 0.830 to 1.066. Spectral shifts are found between 0.65 and 0.75 nanometers. Finally, spatial performance evaluation yielded a point spread function full width at half maximum of 1.27 to 1.75 pixels, a relative edge response of 0.802 to 0.651, and a modulation transfer function at Nyquist of 0.488 to 0.253.

Open-File Report↗
USGS2023

ECCOE Landsat quarterly Calibration and Validation report—Quarter 1, 2023

Executive Summary The U.S. Geological Survey Earth Resources Observation and Science Calibration and Validation (Cal/Val) Center of Excellence (ECCOE) focuses on improving the accuracy, precision, calibration, and product quality of remote-sensing data, leveraging years of multiscale optical system geometric and radiometric calibration and characterization experience. The ECCOE Landsat Cal/Val Team continually monitors the geometric and radiometric performance of active Landsat missions and makes calibration adjustments, as needed, to maintain data quality at the highest level. This report provides observed geometric and radiometric analysis results for Landsats 7–8 for quarter 1 (January–March) of 2023. All data used to compile the Cal/Val analysis results presented in this report are freely available from the U.S. Geological Survey EarthExplorer website: https://earthexplorer.usgs.gov . One specific activity that the ECCOE Landsat Cal/Val Team closely monitored was a Landsat 8 safehold anomaly. On January 26, 2023, the Global Positioning System (GPS) onboard Landsat 8 became invalid because the GPS fault tripped. Later that same day, the GPS was reinitialized, but a Field of View 1 fault trip occurred early the next morning, causing the observatory to go into Earth Point Safe mode, which put the Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) into safehold. Once it was safe to reactivate the sensors, the OLI was transitioned to operational status late on January 27 and TIRS was reactivated early on January 28. Additional information about the Landsat 8 safehold anomaly is here: https://www.usgs.gov/landsat-missions/news/landsat-8-recovers-safehold .

Open-File Report↗
USGS2025

ECCOE Landsat quarterly Calibration and Validation report—Quarter 4, 2024

Executive Summary The U.S. Geological Survey Earth Resources Observation and Science Calibration and Validation (Cal/Val) Center of Excellence focuses on improving the accuracy, precision, calibration, and product quality of remote-sensing data, leveraging years of multiscale optical system geometric and radiometric calibration and characterization experience. The Earth Resources Observation and Science Cal/Val Center of Excellence Landsat Cal/Val Team continually monitors the geometric and radiometric performance of active Landsat missions and makes calibration adjustments, as needed, to maintain data quality at the highest level. This report provides observed geometric and radiometric analysis results for Landsats 8 and 9 for quarter 4 (October–December) of 2024. All data used to compile the Cal/Val analysis results presented in this report are freely available from the U.S. Geological Survey EarthExplorer website: https://earthexplorer.usgs.gov .

Open-File Report↗
USGS1951

Geologic map of the baritic carbonate body near Mountain Pass, San Bernardino County, California

A geologic map of an important deposit of rare earth metals studied recently by Geological Survey geologists near Mountain Pass, California has been completed Secretary of the Interior Oscar L. Chapman announced today. The discovery of this deposit was announced on January 16, and because of the great interest that has been shown in the deposit, the map is being made available for public inspection immediately, Secretary Chapman explained. The deposit covered by this map is in San Bernardino County, California near where prospectors made the original discovery on the Birthday claims in 1949. Subsequent studies by the Geological Survey have shown that an area roughly 6 miles long and 2 miles wide, extending southeast from the original discovery, contains a number of other rare carth-bearing deposits, including the large ore body covered by this map. This ore body is made up largely of a carbonate mineral and barite, but contains significant quantities of the rare earth mineral, bastnasite as well. It is exposed over an area 2,400 feet long and 400 feet wide.

California↗
USGS1958

Periodic heat flow in a stratified medium with application to permafrost problems

Solutions to the Fourier heat equation for quasi-steady periodic flow in a stratified semi-infinite medium can be obtained readily by standard methods. The results have wide application to studies of earth-temperature variations induced by diurnal, annual, and other periodic variations in ground surface temperature. Much of the previous work on this subject has been interpreted with reference to the solution for the homogeneous case; and this can be seriously in error when applied to stratified earth materials. One application of the theory is to the important problem of determining the minimum thickness of gravel fill required to maintain the material on which it rests (the subgrade) in a perennially frozen state in permafrost areas. The results indicate that the required fill thickness is quite sensitive to the thermal properties of the subgrade. If a thin layer of material with low thermal contact coefficient, such as spruce logs, is placed between the fill and subgrade, the thickness of fill required to maintain undisturbed permafrost can be greatly reduced. The thermal properties of the soil beneath the layer supporting plant growth can exercise an important influence on the temperature in that layer. This effect, which cannot be explained by studies of the ground surface and the surficial layer, is likely to have important application to plant ecology in the Arctic.

Open-File Report↗
USGS1965

Ground-water data of selected test holes and wells along the Arkansas river in Muskogee County, Oklahoma

The data in this report were collected during the period 1958-64 by the U.S. Geological Survey in cooperation with the U.S. Army, Corps of Engineers, as part of a comprehensive study of the ground-water resources of the alluvium along the Arkansas and Verdigris Rivers between Moffett and Catoosa, Oklahoma (fig. 1). The purpose of this report is to make the hydrologic data obtained during the study of ground water in the alluvium along the Arkansas River in Muskogee County readily available to the public. The data in this report should be useful in predicting geologic and hydrologic conditions when drilling new wells. Table 1 gives information on the sizes, depths, yields, and other characteristics of wells in the area. The table also provides a key to the additional information for each well site given in tables 2 through 6. Table 2 gives logs for the materials penetrated at test holes and wells in the report area; table 3 gives depths to water measured in wells; table 4 includes chemical analyses of water from wells; table 5 gives laboratory determinations of particle-size distribution of earth samples collected from test holes and wells; and table 6 gives coefficients of permeability and other hydrologic properties of earth samples from the selected test holes. Similar data for Sequoyah County, LeFlore-Haskell Counties, and Wagoner-Rogers Counties are available in other open-file reports. An interpretive report, 'Hydrology of the alluvium of the Arkansas River, Muskogee, Oklahoma, to Fort Smith, Arkansas,' by Harry H. Tanaka and Jerrald R. Hollowell will be published as U.S. Geological Survey Water-Supply Paper 1809-T.

Open-File Report↗
USGS1965

Ground-water data of selected test holes and wells along the Verdigris River in Wagoner and Rogers Counties, Oklahoma

The data in this report were collected during the period 1958-64 by the U.S. Geological Survey in cooperation with the U.S. Army, Corps of Engineers, as part of a comprehensive study of the ground-water resources of the alluvium along the Arkansas and Verdigris Rivers between Moffett and Catoosa, Oklahoma (fig. 1). The purpose of this report is to make the hydrologic data obtained during the study of ground water in the alluvium along the Verdigris River in Wagoner and Rogers Counties readily available to the public. The data in this report should be useful in predicting geologic and hydrologic conditions when drilling new wells. Table 1 gives information on the sizes, depths, yields, and other characteristics of wells in the area. The table also provides a key to the additional information for each well site given in tables 2 through 6. Table 2 gives logs for the materials penetrated at test holes and wells in the report area; table 3 gives depths to water measured in wells; table 4 includes chemical analyses of water from wells; table 5 gives laboratory determinations of particle-size distribution of earth samples collected from test holes and wells; and table 6 gives coefficients of permeability and other hydrologic properties of earth samples from the selected test holes. Similar data for Sequoyah County, LeFlore-Haskell Counties, and Muskogee County are available in other open-file reports. An interpretive report, 'Hydrology of the alluvium of the Arkansas River, Muskogee, Oklahoma, to Fort Smith, Arkansas,' by Harry H. Tanaka and Jerrald R. Hollowell will be published as U.S. Geological Survey Water-Supply Paper 1809-T.

Oklahoma↗
USGS1965

Ground-water data of selected test holes and wells along the Arkansas River in Sequoyah County, Oklahoma

The data in this report were collected during the period 1958-64 by the U.S. Geological Survey in cooperation with the U.S. Army, Corps of Engineers, as part of a comprehensive study of the ground-water resources of the alluvium along the Arkansas and Verdigris Rivers between Moffett and Catoosa, Oklahoma (fig. 1). The purpose of this report is to make the hydrologic data obtained during the study of ground water in the alluvium along the Arkansas River in Sequoyah County readily available to the public. The data in this report should be useful in predicting geologic and hydrologic conditions when drilling new wells. Table 1 gives information on the sizes, depths, yields, and other characteristics of wells in the area. The table also provides a key to the additional information for each well site given in tables 2 through 6. Table 2 gives logs for the materials penetrated at test holes and wells in the report area; table 3 gives depths to water measured in wells; table 4 includes chemical analyses of water from wells; table 5 gives laboratory determinations of particle-size distribution of earth samples collected from test holes and wells; and table 6 gives coefficients of permeability and other hydrologic properties of earth samples from the selected test holes. Similar data for LeFlore-Haskell Counties, Muskogee County, and Wagoner-Rogers Counties are available in other open-file reports. An interpretive report, 'Hydrology of the alluvium of the Arkansas River, Muskogee, Oklahoma, to Fort Smith, Arkansas,' by Harry H. Tanaka and Jerrald R. Hollowell will be published as U.S. Geological Survey Water-Supply Paper 1809-T.

Open-File Report↗
USGS1965

Ground-water data of selected test holes and wells along the Arkansas River in LeFlore and Haskell Counties, Oklahoma

The data in this report were collected during the period 1958-64 by the U.S. Geological Survey in cooperation with the U.S. Army, Corps of Engineers, as part of a comprehensive study of the ground-water resources of the alluvium along the Arkansas and Verdigris Rivers between Moffett and Catoosa, Oklahoma (fig. 1). The purpose of this report is to make the hydrologic data obtained during the study of ground water in the alluvium along the Arkansas River in Le Flore and Haskell Counties readily available to the public. The data in this report should be useful in predicting geologic and hydrologic conditions when drilling new wells. Table 1 gives information on the sizes, depths, yields, and other characteristics of wells in the area. The table also provides a key to the additional information for each well site given in tables 2 through 6. Table 2 gives logs for the materials penetrated at test holes and wells in the report area; table 3 gives depths to water measured in wells; table 4 includes chemical analyses of water from wells; table 5 gives laboratory determinations of particle-size distribution of earth samples collected from test holes and wells; and table 6 gives coefficients of permeability and other hydrologic properties of earth samples from the selected test holes. Similar data for Sequoyah County, Muskogee County, and Wagoner-Rogers Counties are available in other open-file reports. An interpretive report, 'Hydrology of the alluvium of the Arkansas River, Muskogee, Oklahoma, to Fort Smith, Arkansas,' by Harry H. Tanaka and Jerrald R. Hollowell will be published as U.S. Geological Survey Water-Supply Paper 1809-T.

Open-File Report↗
USGS1969

Paleogene floras from the Gulf of Alaska

Numerous collections of fossil plants from the Gulf of Alaska region were obtained from rocks that are well dated by marine mollusks. The mollusks indicate that the oldest possible age for the lowest plant assemblage is middle Eocene (Domengine) and that the youngest possible age for the highest Paleogene plant assemblage is middle Oligocene (Lincoln). Paleobotanical correlations indicate that the lowest plant assemblage is of early late Eocene (early Ravenian) age and the highest plant assemblage is of early Oligocene (Kummerian) age. A new provincial stage--the Angoonian--is proposed, based on assemblages from rocks in southeastern Alaska. The Angoonian is thought to be of late Oligocene (early Blakeley) age. Only one stratigraphically isolated assemblage from the Gulf of Alaska region has been recognized as of Angoonian age. The biostratigraphy of the Gulf of Alaska region and of other regions in Alaska indicates that the Seldovian, Homerian, and Clamgulchian Stages are probably entirely of Neogene age. The early Ravenian assemblages represent Paratropical Rain forest (that is, similar to vegetation of a narrow region bordering the Tropical Rain forest) based on the physiognomic analysis of foliage; the most diverse families represented are Menispermaceae and Icacinaceae. These are accompanied by palms, Anonaceae, tjristicaceae, Dipterocarpaceae, Barringtoniaceae, and Myrtaceae. A minor element is represented by broad-leaved deciduous plants. The middle Ravenian was somewhat cooler, as indicated by foliar physiognomy, the fewer Tropical Rain forest elements, and the diversity of Lauraceae. The late Ravenian assemblage represents a broad-leaved deciduous forest indicating a temperate climate. The Kummerian assemblages were again dominated by Lauraceae, and the physiognomic characters of the foliage indicate that Subtropical forest was again represented. The existence of a broad-leaved evergreen forest in Alaska such as that of the early Ravenian indicates that extended periods of darkness could probably not have existed at that time. The Alaskan Paleogene floras, as well as those from other regions, indicate that the earth's axis of rotation may not have had as great an inclination in the past. Strong climatic fluctuations evidenced by foliar physiognomy of Tertiary floras is thought to have been the result of changes in the inclination of the earth's axis. The history of the development of the Arcto-Tertiary concept is reviewed, and the fundamental lack of evidence for this concept is shown. An alternative, more complex, concept is proposed for the development of the Mixed Mesophytic forest. Paleobotanical evidence indicates that tolerances of many genera have changed during the Tertiary. Many Mixed Mesophytic genera--particularly those that are today temperate outliers of basically tropical groups--may have had a wide distribution in the Paleogene Paratropical Rain and Subtropical forests and have entered the warm temperate forests only during the later Paleogene or Neogene. Some Mixed Mesophytic groups appear to be of later Neogene origin and have been significant members of the warm temperate forests since that time. Some Mixed Mesophytic genera apparently were members of the Paratropical Rain forest only in the earliest Paleogene and became adapted to warm temperate climates by the late Eocene or perhaps even earlier. The Mixed Mesophytic forest may have developed independently in Eurasia, western North America, and eastern North America.

Alaska↗
USGS1974

First EROS/AID International Course on remote sensing

The First International Training Course on Remote Sensing held at the Earth Resources Observations Systems (EROS) Data Center in Sioux Falls, South Dakota, was sponsored by the Agency for International Development (AID), U.S. Department of State, from June 4 to 27, 1973. This course was conducted by the U.S. Geological Survey (USGS) under Participating Agency Services Agreement (PASA) TA (IC) 2-72, 931-11-995-902-72-3138905, as part of the AID program to provide training in remote sensing technology for earth scientists in the less developed countries.

South Dakota↗
USGS1976

Integration of geological remote-sensing techniques in subsurface analysis

Geological remote sensing is defined as the study of the Earth utilizing electromagnetic radiation which is either reflected or emitted from its surface in wavelengths ranging from 0.3 micrometre to 3 metres. The natural surface of the Earth is composed of a diversified combination of surface cover types, and geologists must understand the characteristics of surface cover types to successfully evaluate remotely-sensed data. In some areas landscape surface cover changes throughout the year, and analysis of imagery acquired at different times of year can yield additional geological information. Integration of different scales of analysis allows landscape features to be effectively interpreted. Interpretation of the static elements displayed on imagery is referred to as an image interpretation. Image interpretation is dependent upon: (1) the geologist's understanding of the fundamental aspects of image formation, and (2.) his ability to detect, delineate, and classify image radiometric data; recognize radiometric patterns; and identify landscape surface characteristics as expressed on imagery. A geologic interpretation integrates surface characteristics of the landscape with subsurface geologic relationships. Development of a geologic interpretation from imagery is dependent upon: (1) the geologist's ability to interpret geomorphic processes from their static surface expression as landscape characteristics on imagery, (2) his ability to conceptualize the dynamic processes responsible for the evolution 6f interpreted geologic relationships (his ability to develop geologic models). The integration of geologic remote-sensing techniques in subsurface analysis is illustrated by development of an exploration model for ground water in the Tucson area of Arizona, and by the development of an exploration model for mineralization in southwest Idaho.

Open-File Report↗
USGS1977

Reconnaissance engineering geology of the Metlakatla area, Annette Island, Alaska, with emphasis on evaluation of earthquakes and other geologic hazards

A program to study the engineering geology of most larger Alaska coastal communities and to evaluate their earthquake and other geologic hazards was started following the 1964 Alaska earthquake; this report about the Metlakatla area, Annette Island, is a product of that program. Field-study methods were of a reconnaissance nature, and thus the interpretations in the report are tentative. Landscape of the Metlakatla Peninsula, on which the city of Metlakatla is located, is characterized by a muskeg-covered terrane of very low relief. In contrast, most of the rest of Annette Island is composed of mountainous terrane with steep valleys and numerous lakes. During the Pleistocene Epoch the Metlakatla area was presumably covered by ice several times; glaciers smoothed the present Metlakatla Peninsula and deeply eroded valleys on the rest. of Annette Island. The last major deglaciation was completed probably before 10,000 years ago. Rebound of the earth's crust, believed to be related to glacial melting, has caused land emergence at Metlakatla of at least 50 ft (15 m) and probably more than 200 ft (61 m) relative to present sea level. Bedrock in the Metlakatla area is composed chiefly of hard metamorphic rocks: greenschist and greenstone with minor hornfels and schist. Strike and dip of beds are generally variable and minor offsets are common. Bedrock is of late Paleozoic to early Mesozoic age. Six types of surficial geologic materials of Quaternary age were recognized: firm diamicton, emerged shore, modern shore and delta, and alluvial deposits, very soft muskeg and other organic deposits, and firm to soft artificial fill. A combination map unit is composed of bedrock or diamicton. Geologic structure in southeastern Alaska is complex because, since at least early Paleozoic time, there have been several cycles of tectonic deformation that affected different parts of the region. Southeastern Alaska is transected by numerous faults and possible faults that attest to major movements of the earth's crust. The latest of the major tectonic events in the Metlakatla region occurred in middle Tertiary time; some minor fault activity probably continues today at depth. Along the outer coast of southeastern Alaska and British Columbia, major faulting activity occurs in the form of active, strike-slip movement along the Queen Charlotte fault about 100 mi (160 kin) west-southwest of Metlakatla. Some branching subsidiary faults also may be active, at least one of which may be the Sandspit fault. Many major and smaller earthquakes occur along the outer coast. These shocks are related to movements along the Queen Charlotte fault. A few small earthquakes occur in the region between the outer coast and the Coast Mountains, which includes Metlakatla. 0nly a few earthquakes have been reported as felt at Metlakatla; these shocks and others felt in the region are tabulated. Historically, the closest major earthquake was the magnitude 8.1 Queen Charlotte Islands earthquake of August 22, 1949, which occurred along the Queen Charlotte fault 125 mi (200 km) southwest of Metlakatla. No damage was reported at Metlakatla. The probability of destructive earthquakes affecting Metlakatla is unknown. A consideration of the tectonics and earthquake history of the region, however, suggests that sometime in the future an earthquake with a magnitude of about 8 will occur along that segment of the Queen Charlotte fault nearest to Metlakatla. Smaller earthquakes with magnitudes of 6 or more might occur elsewhere in the Metlakatla region or south-southeastward near Dixon Entrance or Hecate Strait. Several geologic effects that have characterized large earthquakes elsewh6re may be expected to accompany some of the possible major earthquakes that might affect the Metlakatla area in the future. Evaluation of effects indicates that fault displacement and tectonic uplift or subsidence are probably unlikely, and ground shaking in general probably would be strongest

Open-File Report↗
USGS1978

Gold, base-metal, and related deposits of North Carolina

Gold, silver, copper, lead, zinc, pyrite, tin, cobalt, molybdenum, tungsten, barite, and rare-earths have been mined in North Carolina. Gold, with by-product silver, occurs in veins and mineralized shear zones in metamorphic rocks of the Piedmont province and in placers derived from these deposits. Copper occurs with complex sulfide ores in quartz veins in the metamorphic rocks of the Piedmont province and in massive pyrrhotite-pyrite deposits in crystalline rocks west of the Blue Ridge. Lead and zinc occur in complex ores of gold, copper, lead, zinc, and silver in veins and replacements in metamorphic rocks. Pyrite occurs in crystalline metamorphic rocks. Tin occurs in pegmatite and placer deposits in crystalline rocks near Kings Mountain. Cobalt minerals with ores of iron or gold have been reported in a few areas in the Piedmont. Molybdenum occurs along the borders of a granite body in Halifax County. Tungsten minerals occur with copper sulfide ores in Cabarrus and Vance Counties. Barite occurs in quartz veins and associated with sulfide minerals in Orange, Madison, Cleveland, and Gaston Counties. Ore-earths occur with sulfides in vein deposits in Cabarrus County.

Open-File Report↗
USGS1978

Notes on availability of multi-channel seismic processing programs

During the past two years, a seismic processing system has been developed within Western Region offices of the U.S. Geological Survey (Pacific-Arctic Branch of Marine Geology). This brief report describes some of the programs within this system that may be of value to others. We process seismic reflection data taken onboard ship to yield a pseudo cross section of the earth as revealed by echoes returned off rock layers within the earth.

Open-File Report↗