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At least 91 records · Page 5Linked to original sources
USGS1995

Volcanic activity in Alaska: Summary of events and response of the Alaska Volcano Observatory 1994

During 1994, the Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, or false alarms at nine volcanic centers-- Mount Sanford, Iliamna, the Katmai group, Kupreanof, Mount Veniaminof, Shishaldin, Makushin, Mount Cleveland and Kanaga (table 1). Of these volcanoes, AVO has a real time, continuously recording seismic network only at Iliamna, which is located in the Cook Inlet area of south-central Alaska (fig. 1). AVO has dial-up access to seismic data from a 5-station network in the general region of the Katmai group of volcanoes. The remaining unmonitored volcanoes are located in sparsely populated areas of the Wrangell Mountains, the Alaska Peninsula, and the Aleutian Islands (fig. 1). For these volcanoes, the AVO monitoring program relies chiefly on receipt of pilot reports, observations of local residents and analysis of satellite imagery.

Alaska↗
USGS1996

Mean annual runoff, precipitation, and evapotranspiration in the glaciated northeastern United States, 1951-80

Two maps, compiled at 1:1 million scale, depict mean annual runoff, precipitation, and evapotranspiration in the part of the United States east of Cleveland, Ohio and north of the southern limit of glaciation. The maps are mutually consistent in that runoff equals precipitation minus evapotranspiration everywhere. The runoff map is based on records of streamflow from 503 watersheds in the United States and southernmost Canada, adjusted to/1951-80 and supplemented by records of precipitation at 483 stations. Precipitation at each station was partitioned into point estimates of runoff and evapotranspiration, which were constrained such that the evapotranspiration estimates varied smoothly across the region and decreased with increasing latitude and altitude, and the runoff estimates were consistent with measured runoff from nearby watersheds. A point estimate of runoff was allowed to equal mean runoff in a nearby watershed, or to be somewhat higher (or lower) if a compensating departure from mean watershed runoff could be inferred in distant parts of the watershed on the basis of altitude or regional trends. Then,precipitation contours were drawn to parallel runoff contours but differ from them by the magnitude of nearby estimates of evapotranspiration. These maps may slightly underrepresent mean precipitation and evapotranspiration in areas of high relief, because most precipitation stations in such areas are in valleys. Map accuracy is evaluated. The maps and text are designed to be printed as 34x53 inch plates; they may not be legible if printed in their entirety at appreciably smaller scales. The Arc/Info coverages from which these maps were prepared are available at the Water Resources National Spatial Data Infrastructure Node : ofr96395_eva , ofr96395_pre , and ofr96395_run (evapotranspiration, precipitation, and runoff). Descriptors: *Annual Runoff, *Areal precipitation, *Runoff, *Evapotranspiration Precipitation, Rainfall, New York, New England, Northeast

Open-File Report↗
USGS1997

Digital data sets that describe aquifer characteristics of the Central Oklahoma Aquifer in central Oklahoma

ARC/INFO export files The data sets in this report include digitized aquifer boundaries and maps of hydraulic conductivity, recharge, and ground-water level elevation contours for the Central Oklahoma aquifer in central Oklahoma. This area encompasses all or part of Cleveland, Lincoln, Logan, Oklahoma, Payne, and Pottawatomie Counties. The Central Oklahoma aquifer includes the alluvial and terrace deposits along major streams, the Garber Sandstone and Wellington Formations, and the Chase, Council Grove, and Admire Groups. The Quaternary-age alluvial and terrace deposits consist of unconsolidated clay, silt, sand, and gravel. The Permian-age Garber Sandstone and Wellington Formations consist of sandstone with interbedded siltstone and mudstone. The Permian-age Chase, Council Grove, and Admire Groups consist of sandstone, shale, and thin limestone. The Central Oklahoma aquifer underlies about 3,000 square miles of central Oklahoma where the aquifer is used extensively for municipal, industrial, commercial, and domestic water supplies. Most of the usable ground water within the aquifer is from the Garber Sandstone and Wellington Formations. Substantial quantities of usable ground water also are present in the Chase, Council Grove, and Admire Groups, and in alluvial and terrace deposits associated with the major streams. The aquifer boundaries, hydraulic conductivity and recharge values, and ground-water level elevation contours are from previously published reports.

Oklahoma↗
USGS1999

1997 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

The Alaska Volcano Observatory (AVO) monitors over 40 historically active volcanoes along the Aleutian Arc. Twenty are seismically monitored and for the rest, the AVO monitoring program relies mainly on pilot reports, observations of local residents and ship crews, and daily analysis of satellite images. In 1997, AVO responded to eruptive activity or suspect volcanic activity at 11 volcanic centers: Wrangell, Sanford, Shrub mud volcano, Iliamna, the Katmai group (Martin, Mageik, Snowy, and Kukak volcanoes), Chiginagak, Pavlof, Shishaldin, Okmok, Cleveland, and Amukta. Of these, AVO has real-time, continuously recording seismic networks at Iliamna, the Katmai group, and Pavlof. The phrase “suspect volcanic activity” (SVA), used to characterize several responses, is an eruption report or report of unusual activity that is subsequently determined to be normal or enhanced fumarolic activity, weather-related phenomena, or a non-volcanic event. In addition to responding to eruptive activity at Alaska volcanoes, AVO also disseminated information for the Kamchatkan Volcanic Eruption Response Team (KVERT) about the 1997 activity of 5 Russian volcanoes--Sheveluch, Klyuchevskoy, Bezymianny, Karymsky, and Alaid (SVA). This report summarizes volcanic activity and SVA in Alaska during 1997 and the AVO response, as well as information on the reported activity at the Russian volcanoes. Only those reports or inquiries that resulted in a “significant” investment of staff time and energy (here defined as several hours or more for reaction, tracking, and follow-up) are included. AVO typically receives dozens of reports throughout the year of steaming, unusual cloud sightings, or eruption rumors. Most of these are resolved quickly and are not tabulated here as part of the 1997 response record.

Alaska↗
USGS2006

Status of water levels and selected water-quality conditions in the Sparta-Memphis aquifer in Arkansas, Spring-Summer 2003

During the spring of 2003, water levels were measured in 341 wells in the Sparta-Memphis aquifer in Arkansas. Waterquality samples were collected for temperature and specificconductance measurements during the spring-summer of 2003 from 70 wells in Arkansas in the Sparta-Memphis aquifer. Maps of areal distribution of potentiometric surface, change in waterlevel measurements from 1999 to 2003, and specific-conductance data reveal spatial trends across the study area. The highest water-level altitude measured in Arkansas was 328 feet above National Geodetic Vertical Datum of 1929 (NGVD of 1929) in Craighead County; the lowest water-level altitude was 199 feet below NGVD of 1929 in Union County. Three large cones of depression are shown in the 2003 potentiometric surface map, centered in Columbia, Jefferson, and Union Counties in Arkansas as a result of large withdrawals for industrial and public supplies. A broad depression exists in western Poinsett County in Arkansas. The potentiometric surface indicates that large withdrawals have altered or reversed the natural direction of flow in most areas. In the northern third of the study area the flow is from the east, west, and north towards the broad depression in Poinsett County. In the central third of the study area the flow is dominated by the cone of depression centered in Jefferson County. In the southern third of the study area the flow is dominated by the two cones of depression in Union and Columbia Counties. A map of water-level changes from 1999 to 2003 was constructed using water-level measurements from 281 wells. The largest rise in water level measured was about 57.8 feet in Columbia County. The largest decline in water level measured was about -71.6 feet in Columbia County. Areas with a general rise are shown in Arkansas, Bradley, Calhoun, Cleveland, Columbia, Ouachita, and Union Counties. Areas with a general decline are shown in Craighead, Crittenden, Cross, Desha, Drew, Jefferson, Lonoke, Phillips, Poinsett, Prairie, and Woodruff Counties. Hydrographs were constructed for wells with a minimum of 25 years of water-level measurements. A trend line using a linear regression was calculated for the period of record from spring of 1978 to spring of 2003 to determine the annual decline or rise in feet per year for water levels in each well. The hydrographs were grouped by county. The mean values for county annual water-level decline or rise ranged from -1.42 to 0.27 foot per year. Specific conductance ranged from 82 microsiemens per centimeter at 25 degrees Celsius in Jefferson County to about 1,210 microsiemens per centimeter at 25 degrees Celsius in Lee County. The mean specific conductance was 400 microsiemens per centimeter at 25 degrees Celsius.

Scientific Investigations Report↗
USGS2006

Use of Spatial Sampling and Microbial Source-Tracking Tools for Understanding Fecal Contamination at Two Lake Erie Beaches

Source-tracking tools were used to identify potential sources of fecal contamination at two Lake Erie bathing beaches: an urban beach (Edgewater in Cleveland, Ohio) and a beach in a small city (Lakeshore in Ashtabula, Ohio). These tools included identifying spatial patterns of Escherichia coli (E. coli) concentrations in each area, determining weather patterns that caused elevated E. coli, and applying microbial source tracking (MST) techniques to specific sites. Three MST methods were used during this study: multiple antibiotic resistance (MAR) indexing of E. coli isolates and the presence of human-specific genetic markers within two types of bacteria, the genus Bacteroides and the species Enterococcus faecium. At Edgewater, sampling for E. coli was done during 2003-05 at bathing-area sites, at nearshore lake sites, and in shallow ground water in foreshore and backshore areas. Spatial sampling at nearshore lake sites showed that fecal contamination was most likely of local origin; E. coli concentrations near the mouths of rivers and outfalls remote to the beach were elevated (greater than 235 colony-forming units per 100 milliliters (CFU/100 mL)) but decreased along transport pathways to the beach. In addition, E. coli concentrations were generally highest in bathing-area samples collected at 1- and 2-foot water depths, midrange at 3-foot depths, and lowest in nearshore lake samples typically collected 150 feet from the shoreline. Elevated E. coli concentrations at bathing-area sites were generally associated with increased wave heights and rainfall, but not always. E. coli concentrations were often elevated in shallow ground-water samples, especially in samples collected less than 10 feet from the edge of water (near foreshore area). The interaction of shallow ground water and waves may be a mechanism of E. coli storage and accumulation in foreshore sands. Infiltration of bird feces through sand with surface water from rainfall and high waves may be concentrating E. coli in shallow ground water in foreshore and backshore sands. At Lakeshore, sampling for E. coli was done at bathing-area, nearshore lake, and parking-lot sites during 2004-05. Low concentrations of E. coli at nearshore lake sites furthest from the shoreline indicated that fecal contamination was most likely of local origin. High concentrations of E. coli in water and bed sediments at several nearshore lake sites showed that contamination was emanating from several points along the shoreline during wet and dry weather, including the boat ramp, an area near the pond drainage, and parking-lot sediments. Physical evidence confirmed that runoff from the parking lot leads to degradation of water quality at the beach. MST samples were collected to help interpret spatial findings and determine whether sources of fecal contamination were from wastewater or bird feces and if a human-specific marker was present. MAR indices were useful in distinguishing between bird feces and wastewater sources because they were about 10 times higher in the latter. The results from MAR indices agreed with results from the two human-specific markers in some but not all of the samples tested. Bacteroides and enterococci human-specific markers were found on one day at Edgewater and two days at Lakeshore. On three days at Edgewater and two days at Lakeshore, the MAR index indicated a mixed source, but neither marker was found in bathing-water samples; this may be because bacterial indicator concentrations were too low to detect a marker. Multiple tools are needed to help identify sources of fecal contamination at coastal beaches. Spatial sampling identified patterns in E. coli concentrations and yielded information on the physical pathways of contamination. MST methods provided information on whether the source was likely of human or nonhuman origin only; however, MST did not provide information on the pathways of contamination.

Scientific Investigations Report↗
USGS2007

Potentiometric Surfaces and Water-Level Trends in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2006

The Cockfield Formation of Claiborne Group and the Wilcox Group contain aquifers that provide sources of ground water in southern and northeastern Arkansas. In 2000, about 9.9 million gallons per day was withdrawn from the Cockfield Formation of Claiborne Group and about 22.2 million gallons per day was withdrawn from the Wilcox Group. Major withdrawals from the aquifers were for industrial and public water supplies. A study was conducted by the U.S. Geological Survey in cooperation with the Arkansas Natural Resources Commission and the Arkansas Geological Survey to determine the water level associated with the aquifers in the Cockfield Formation of Claiborne Group and the Wilcox Group in southern and northeastern Arkansas. During February and March 2006, 56 water-level measurements were made in wells completed in the Cockfield aquifer and 59 water-level measurements were made in wells completed in the Wilcox aquifer, 16 in southwestern and 43 in northeastern Arkansas. This report presents the results as potentiometric-surface maps and as long-term water-level hydrographs. The regional direction of ground-water flow in the Cockfield Formation of Claiborne Group generally is towards the east and southeast, away from the outcrop, except in areas of intense ground-water withdrawals, such as western Drew County, southeastern Lincoln County, southwestern Calhoun County, and near Crossett in Ashley County. There are three cones of depression indicated by relatively low water-level altitudes in southeastern Lincoln County, southwestern Calhoun County, and near Crossett in Ashley County. The lowest water-level altitude measured was 44 feet above the National Geodetic Vertical Datum of 1929 in Lincoln County; the highest water-level altitude measured was 346 feet above the National Geodetic Vertical Datum of 1929 in Columbia County at the outcrop area. Hydrographs from 40 wells with historical water levels from 1986 to 2006 were evaluated using linear regression to calculate the annual rise or decline. Calhoun and Cleveland Counties have mean annual rises from 0.01 to 0.07 feet per year. Arkansas, Ashley, Bradley, Chicot, Columbia, Drew, Lincoln, and Union Counties have mean annual declines from 0.4 to 0.55 feet per year. Desha County has a mean annual decline of about 1.35 feet per year. The direction of ground-water flow in the southwestern study area of the Wilcox Group generally is south and east. The lowest water-level altitude measured in southwestern Arkansas was 147 feet above the National Geodetic Vertical Datum of 1929 near the Ouachita River in Clark County; the highest water-level altitude measured was 397 feet above the National Geodetic Vertical Datum of 1929 in the outcrop area of Hempstead County. The direction of ground-water flow in the northeastern study area of the Wilcox Group generally is south and east. The lowest water-level altitude measured in northeastern Arkansas was 120 feet above the National Geodetic Vertical Datum of 1929 near West Memphis in Crittenden County; the highest water-level altitude measured was 368 feet above the National Geodetic Vertical Datum of 1929 on Crowleys Ridge in Clay County. Hydrographs from 28 wells with historical water levels from 1986 to 2006 were evaluated using linear regression to calculate the annual rise or decline. All 28 wells showed an annual decline from 1986 to 2006. Craighead, Greene, Mississippi, and Poinsett Counties have mean annual declines from 0.27 to 1.00 feet per year. Crittenden, Lee, and St. Francis Counties have mean annual declines from 1.39 to 1.64 feet per year.

Scientific Investigations Report↗
USGS2009

Water Levels and Selected Water-Quality Conditions in the Sparta-Memphis Aquifer (Middle Claiborne Aquifer) in Arkansas, Spring-Summer 2007

The U.S. Geological Survey in cooperation with the Arkansas Natural Resources Commission and the Arkansas Geological Survey has monitored water levels in the Sparta Sand of Claiborne Group and Memphis Sand of Claiborne Group (herein referred to as the Sparta Sand and the Memphis Sand, respectively), since the 1920s. Groundwater withdrawals have increased while water levels have declined since monitoring was initiated. Herein, aquifers in the Sparta Sand and Memphis Sand will be referred to as the Sparta-Memphis aquifer throughout Arkansas. During the spring of 2007, 309 water levels were measured in wells completed in the Sparta-Memphis aquifer. During the summer of 2007, 129 water-quality samples were collected and measured for temperature and specific conductance and 102 were collected and analyzed for chloride from wells completed in the Sparta-Memphis aquifer. Water-level measurements collected in wells screened in the Sparta-Memphis aquifer were used to produce a regional potentiometric-surface map. The regional direction of groundwater flow in the Sparta-Memphis aquifer is generally to the south-southeast in the northern half of Arkansas and to the east and south in the southern half of Arkansas, away from the outcrop area except where affected by large ground-water withdrawals. The highest water-level altitude measured in the Sparta-Memphis aquifer was 326 feet above National Geodetic Vertical Datum of 1929, located in Grant County in the outcrop at the western boundary of the study area; the lowest water-level altitude was 161 feet below National Geodetic Vertical Datum of 1929 in Union County near the southern boundary of the study area. Eight cones of depression (generally represented by closed contours) are located in the following counties: Bradley, Drew, and Ashley; Calhoun; Cleveland; Columbia; Crittenden; Arkansas, Jefferson, and Lincoln; Cross and Poinsett; and Union. Two large depressions are shown on the 2007 potentiometric-surface map, centered in Jefferson and Union Counties, as a result of large withdrawals for industrial and public supplies. The depression centered in Jefferson County deepened and expanded in recent years into Arkansas and Prairie Counties as a result of large withdrawals for irrigation and public supply. The area enclosed within the 40-foot contour has expanded on the 2007 potentiometric-surface map when compared with the 2005 potentiometric-surface map. In 2003, the depression in Union County was elongated east and west and beginning to coalesce with the depression in Columbia County. The deepest measurement during 2007 in the center of the depression in Union County has risen 38 feet since 2003. The area enclosed by the deepest contour, 160 feet below National Geodetic Vertical Datum of 1929, on the 2007 potentiometric-surface map is less than 10 percent of the area on the 2005 potentiometric-surface map. A broad depression in western Poinsett and Cross Counties was first shown in the 1995 potentiometric-surface map caused by withdrawals for irrigation extending north to the Poinsett-Craighead County line, and south into Cross County. A water-level difference map was constructed using the difference between water-level measurements made during 2003 and 2007 from 283 wells. The difference in water level between 2003 and 2007 ranged from -49.8 to 60.0 feet. Areas with a general rise in water levels are shown in northern Arkansas, Columbia, southern Jefferson, and most of Union Counties. In the area around west-central Union County, water levels rose as much as 60.0 feet with water levels in 15 wells rising 20 feet or more, which is an average annual rise of 5 feet or more. Water levels generally declined throughout most of the rest of Arkansas. Hydrographs from 157 wells were constructed with a minimum of 25 years of water-level measurements. During the period 1983-2007, the county mean annual water level rose in Calhoun, Columbia, Hot Spring, and Lafayette Counties. Mean an

Scientific Investigations Report↗
USGS2009

Comparison of the Immunomagnetic Separation/Adenosine Triphosphate Rapid Method and the Modified mTEC Membrane-Filtration Method for Enumeration of Escherichia coli

Water quality at beaches is monitored for fecal indicator bacteria by traditional, culture-based methods that can take 18 to 24 hours to obtain results. A rapid detection method that provides estimated concentrations of fecal indicator bacteria within 1 hour from the start of sample processing would allow beach managers to post advisories or close the beach when the conditions are actually considered unsafe instead of a day later, when conditions may have changed. A rapid method that couples immunomagnetic separation with adenosine triphosphate detection (IMS/ATP rapid method) was evaluated through monitoring of Escherichia coli (E. coli) at three Lake Erie beaches in Ohio (Edgewater and Villa Angela in Cleveland and Huntington in Bay Village). Beach water samples were collected between 4 and 5 days per week during the recreational seasons (May through September) of 2006 and 2007. Composite samples were created in the lab from two point samples collected at each beach and were shown to be comparable substitutes for analysis of two individual samples. E. coli concentrations in composite samples, as determined by the culture-based method, ranged from 4 to 24,000 colony-forming units per 100 milliliters during this study across all beaches. Turbidity also was measured for each sample and ranged from 0.8 to 260 neophelometric turbidity ratio units. Environmental variables were noted at the time of sampling, including number of birds at the beach and wave height. Rainfall amounts were measured at National Weather Service stations at local airports. Turbidity, rainfall, and wave height were significantly related to the culture-based method results each year and for both years combined at each beach. The number of birds at the beach was significantly related to the culture-based method results only at Edgewater during 2006 and during both years combined. Results of the IMS/ATP method were compared to results of the culture-based method for samples by year for each beach. The IMS/ATP method underwent several changes and refinements during the first year, including changes in reagents and antibodies and alterations to the method protocol. Because of the changes in the method, results from the two years of study could not be combined. Kendall's tau correlation coefficients for relations between the IMS/ATP and culture-based methods were significant except for samples collected during 2006 at Edgewater and for samples collected during 2007 at Villa Angela. Further, relations were stronger for samples collected in 2006 than for those collected in 2007, except at Edgewater where the reverse was observed. The 2007 dataset was examined to identify possible reasons for the observed difference in significance of relations by year. By dividing the 2007 data set into groups as a function of sampling date, relations (Kendall's tau) between methods were observed to be stronger for samples collected earlier in the season than for those collected later in the season. At Edgewater and Villa Angela, there were more birds at the beach at time of sampling later in the season compared to earlier in the season. (The number of birds was not examined at Huntington.) Also, more wet days (when rainfall during the 24 hours prior to sampling was greater than 0.05 inch) were sampled later in the season compared to earlier in the season. Differences in the dominant fecal source may explain the change in the relations between the culture-based and IMS/ATP methods.

Scientific Investigations Report↗
USGS2010

Potentiometric Surfaces and Water-Level Trends in the Cockfield (Upper Claiborne) and Wilcox (Lower Wilcox) Aquifers of Southern and Northeastern Arkansas, 2009

Eocene-age sand beds near the base of the Cockfield Formation of Claiborne Group constitute the aquifer known locally as the Cockfield aquifer. Upper-Paleocene age sand beds within the lower parts of the Wilcox Group constitute the aquifer known locally as the Wilcox aquifer. In 2005, reported water withdrawals from the Cockfield aquifer in Arkansas totaled 16.1 million gallons per day, while reported water withdrawals from the Wilcox aquifer in Arkansas totaled 27.0 million gallons per day. Major withdrawals from these units were for industrial and public water supplies with lesser but locally important withdrawals for commercial, domestic, and agricultural uses. During February 2009, 56 water-level measurements were made in wells completed in the Cockfield aquifer and 57 water-level measurements were made in wells completed in the Wilcox aquifer. The results from the 2009 water-level measurements are presented in potentiometric-surface maps and in combination with previous water-level measurements. Trends in water-level change over time within the two aquifers are investigated using water-level difference maps and well hydrographs. Water-level difference maps were constructed for each aquifer using the difference between depth to water measurements made in 2003 to 2009. Well hydrographs for each aquifer were constructed for wells with 20 or more years of historical water-level data. The hydrographs were evaluated individually using linear regression to calculate the annual rise or decline in water levels, and by aggregating the regression results by county and statistically summarizing for the range, mean, and median water-level change in each county. The 2009 potentiometric surface of the Cockfield aquifer map indicates the regional direction of groundwater flow generally towards the east and southeast, except in two areas of intense groundwater withdrawals that have developed into cones of depression. The lowest water-level altitude measured was 43 feet and the highest water-level altitude measured was 351 feet. A water-level difference map was constructed from 54 wells completed in the Cockfield aquifer within Arkansas. The largest rise in water level was 14.9 feet and the largest decline was 27.4 feet. Seven wells had a rise in water level, and the remaining 47 wells had a decline in water level. Hydrographs for 33 wells completed in the Cockfield aquifer were developed. Hydrographs indicate water-level changes in individual wells ranged from rises of 0.33 feet per year to declines of 1.21 feet per year over the 20-year period (1990-2009). County summaries of the linear regression analysis indicate Cleveland and Columbia Counties have mean annual rises. Arkansas, Ashley, Bradley, Calhoun, Chicot, Desha, Drew, Lincoln, and Union Counties have mean annual declines. The potentiometric surface for the Wilcox aquifer is presented using two maps, one for a southern area and another for a northeastern area, because of the absence of water-level data in the central part of the State. The direction of groundwater flow in the southern area is generally the east, except around two cones of depression and around two mounds of elevated water levels. Water-level altitudes in the southern area range from 147 feet to 400 feet. The direction of groundwater flow in the northeastern area is generally to the south and southeast except in an area of intense groundwater withdrawals that has altered the flow to a westerly direction. Two water-level difference maps were constructed using water-level altitudes measured in 2003 to 2009 from 53 wells completed in the Wilcox aquifer within southern and northeastern Arkansas. In the southern area the largest rise in water level was 16.0 feet and the largest decline was 17.7 feet. Eight wells in the southern area had rising water levels and the remaining five wells had declining water levels. In the northeastern area, the largest rise in water level was 1.3 feet and the larg

Scientific Investigations Report↗
USGS2011

2008 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest or suspected unrest at seven separate volcanic centers in Alaska during 2008. Significant explosive eruptions at Okmok and Kasatochi Volcanoes in July and August dominated Observatory operations in the summer and autumn. AVO maintained 24-hour staffing at the Anchorage facility from July 12 through August 28. Minor eruptive activity continued at Veniaminof and Cleveland Volcanoes. Observed volcanic unrest at Cook Inlet's Redoubt Volcano presaged a significant eruption in the spring of 2009. AVO staff also participated in hazard communication regarding eruptions or unrest at nine volcanoes in Russia as part of a collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

Alaska, Kamchatka↗
USGS2013

Analysis of environmental setting, surface-water and groundwater data, and data gaps for the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, through 2011

The Citizen Potawatomi Nation Tribal Jurisdictional Area, consisting of approximately 960 square miles in parts of three counties in central Oklahoma, has an abundance of water resources, being underlain by three principal aquifers (alluvial/terrace, Central Oklahoma, and Vamoosa-Ada), bordered by two major rivers (North Canadian and Canadian), and has several smaller drainages. The Central Oklahoma aquifer (also referred to as the Garber-Wellington aquifer) underlies approximately 3,000 square miles in central Oklahoma in parts of Cleveland, Logan, Lincoln, Oklahoma, and Pottawatomie Counties and much of the tribal jurisdictional area. Water from these aquifers is used for municipal, industrial, commercial, agricultural, and domestic supplies. The approximately 115,000 people living in this area used an estimated 4.41 million gallons of fresh groundwater, 12.12 million gallons of fresh surface water, and 8.15 million gallons of saline groundwater per day in 2005. Approximately 8.48, 2.65, 2.24, 1.55, 0.83, and 0.81 million gallons per day of that water were used for domestic, livestock, commercial, industrial, crop irrigation, and thermoelectric purposes, respectively. Approximately one-third of the water used in 2005 was saline water produced during petroleum production. Future changes in use of freshwater in this area will be affected primarily by changes in population and agricultural practices. Future changes in saline water use will be affected substantially by changes in petroleum production. Parts of the area periodically are subject to flooding and severe droughts that can limit available water resources, particularly during summers, when water use increases and streamflows substantially decrease. Most of the area is characterized by rural types of land cover such as grassland, pasture/hay fields, and deciduous forest, which may limit negative effects on water quality by human activities because of lesser emissions of man-made chemicals on such areas than in more urbanized areas. Much of the water in the area is of good quality, though some parts of this area have water quality impaired by very hard surface water and groundwater; large chloride concentrations in some smaller streams; relatively large concentrations of nutrients and counts of fecal-indicator bacteria in the North Canadian River; and chloride, iron, manganese, and uranium concentrations that exceed primary or secondary drinking-water standards in water samples collected from small numbers of wells. Substantial amounts of hydrologic and water-quality data have been collected in much of this area, but there are gaps in those data caused by relatively few streamflow-gaging stations, uneven distribution of surface-water quality sampling sites, lack of surface-water quality sampling at high-flow and low-flow conditions, and lack of a regularly measured and sampled groundwater network. This report summarizes existing water-use, climatic, geographic, hydrologic, and water-quality data and describes several means of filling gaps in hydrologic data for this area.

Oklahoma↗
USGS2013

Water levels and water quality in the Sparta-Memphis aquifer (middle Claiborne aquifer) in Arkansas, spring-summer 2009

The U.S. Geological Survey in cooperation with the Arkansas Natural Resources Commission and the Arkansas Geological Survey has monitored water levels in the Sparta Sand of Claiborne Group and Memphis Sand of Claiborne Group (herein referred to as the Sparta Sand and the Memphis Sand, respectively) since the 1920s. Groundwater withdrawals have increased while water levels have declined since monitoring was initiated. Herein, aquifers in the Sparta Sand and Memphis Sand will be referred to as the Sparta-Memphis aquifer throughout Arkansas. During the spring of 2009, 324 water levels were measured in wells completed in the Sparta-Memphis aquifer and used to produce a regional potentiometric-surface map. During the summer of 2009, 64 water-quality samples were collected and measured for specific conductance, temperature, and pH from wells completed in the Sparta-Memphis aquifer. The regional direction of groundwater flow in the Sparta-Memphis aquifer is generally to the south-southeast in the northern half of Arkansas and to the east and south in the southern half of Arkansas, away from the outcrop area except where affected by large groundwater withdrawals. The highest and lowest water-level altitudes measured in the Sparta-Memphis aquifer were 325 feet above and 157 feet below National Geodetic Vertical Datum of 1929, respectively. Eight depressions (generally represented by closed contours) are located in the following counties: Bradley; Ashley; Calhoun; Cleveland; Columbia; Arkansas, Jefferson, Lincoln, and Prairie; Cross and Poinsett; and Union. Two large depressions shown on the 2009 potentiometric-surface map, centered in Jefferson and Union Counties, are the result of large withdrawals for industrial, irrigation, or public supply. The depression centered in Jefferson County deepened and expanded in recent years into Arkansas and Prairie Counties. The area enclosed within the 40-foot contour on the 2009 potentiometric-surface map has expanded south to the Drew County line and moved west from the intersection of Arkansas, Jefferson, and Lincoln Counties when compared with the 2007 potentiometric-surface map. To the north, east, and west, the 40-foot contour is comparable to the 2007 potentiometric-surface map. The lowest water-level altitude measurement during 2009 in the center of the depression in Union County represents a rise of 42 feet since 2003. The area enclosed by the lowest altitude contour, 140 feet below National Geodetic Vertical Datum of 1929, on the 2009 potentiometric-surface map is about half the area on the 2007 potentiometric-surface map. In the depression in western Poinsett and Cross Counties, the 140-foot contour extended north to the Poinsett-Craighead County line and south across Cross County about two-thirds of the distance to the St. Francis County line. A water-level difference map was constructed using water-level measurements made during 2005 and 2009 from 309 wells. The difference in water level between 2005 and 2009 ranged from -74.6 to 60.2 feet. Areas with a general rise in water levels occur in central Columbia County, southern Jefferson County, and most of Union County. In the area around west-central Union County, water levels rose as much as 60.2 feet with water levels in 18 wells rising 20 feet or more, representing an average annual rise of 5 feet or more. Water levels generally declined throughout most of the rest of Arkansas. Hydrographs were constructed using a minimum of 25 years of water-level measurements at each of 206 wells. During the period 1985–2009, mean annual water levels rose in Calhoun, Columbia, Lafayette, and Union Counties, about 1.3 feet per year (ft/yr), 0.2 ft/yr, 0.1 ft/yr, and 0.6 ft/yr, respectively. Mean annual water-level declines between 0.0 and 2.3 ft/yr occurred in all other counties. In western Arkansas County, water-level altitudes in a continuously monitored well declined 60 feet during the irrigation season (April to September). Specific conductance ranged from 43 microsiemens per centimeter at 25 degrees Celsius (μS/cm) in Ouachita County to 1,230 μS/cm in Phillips County. The mean specific conductance was 392 μS/cm. Although there is a regional increase in specific conductance to the east and south, specific conductance values greater than 700 μS/cm occurred in samples from wells in Arkansas, Ashley, Monroe, Phillips, and Union Counties.

Arkansas↗
USGS2014

Hydrogeology and simulation of groundwater flow in the Central Oklahoma (Garber-Wellington) Aquifer, Oklahoma, 1987 to 2009, and simulation of available water in storage, 2010–2059

The Central Oklahoma (Garber-Wellington) aquifer underlies about 3,000 square miles of central Oklahoma. The study area for this investigation was the extent of the Central Oklahoma aquifer. Water from the Central Oklahoma aquifer is used for public, industrial, commercial, agricultural, and domestic supply. With the exception of Oklahoma City, all of the major communities in central Oklahoma rely either solely or partly on groundwater from this aquifer. The Oklahoma City metropolitan area, incorporating parts of Canadian, Cleveland, Grady, Lincoln, Logan, McClain, and Oklahoma Counties, has a population of approximately 1.2 million people. As areas are developed for groundwater supply, increased groundwater withdrawals may result in decreases in long-term aquifer storage. The U.S. Geological Survey, in cooperation with the Oklahoma Water Resources Board, investigated the hydrogeology and simulated groundwater flow in the aquifer using a numerical groundwater-flow model. The purpose of this report is to describe an investigation of the Central Oklahoma aquifer that included analyses of the hydrogeology, hydrogeologic framework of the aquifer, and construction of a numerical groundwater-flow model. The groundwater-flow model was used to simulate groundwater levels and for water-budget analysis. A calibrated transient model was used to evaluate changes in groundwater storage associated with increased future water demands.

Oklahoma↗
USGS2014

2010 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest or suspected unrest at 12 volcanic centers in Alaska during 2010. The most notable volcanic activity consisted of intermittent ash emissions from long-active Cleveland volcano in the Aleutian Islands. AVO staff also participated in hazard communication regarding eruptions or unrest at seven volcanoes in Russia as part of an ongoing collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

Alaska↗
USGS2014

2012 volcanic activity in Alaska: Summary of events and response of the Alaska Volcano Observatory

The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest, or suspected unrest at 11 volcanic centers in Alaska during 2012. Of the two verified eruptions, one (Cleveland) was clearly magmatic and the other (Kanaga) was most likely a single phreatic explosion. Two other volcanoes had notable seismic swarms that probably were caused by magmatic intrusions (Iliamna and Little Sitkin). For each period of clear volcanic unrest, AVO staff increased monitoring vigilance as needed, reviewed eruptive histories of the volcanoes in question to help evaluate likely outcomes, and shared observations and interpretations with the public. 2012 also was the 100th anniversary of Alaska’s Katmai-Novarupta eruption of 1912, the largest eruption on Earth in the 20th century and one of the most important volcanic eruptions in modern times. AVO marked this occasion with several public events.

Alaska↗
USGS2015

Potentiometric surfaces and water-level trends in the Cockfield (upper Claiborne) aquifer in southern Arkansas and the Wilcox (lower Wilcox) aquifer of northeastern and southern Arkansas, 2012

The Cockfield aquifer, located in southern Arkansas, is composed of Eocene-age sand beds found near the base of the Cockfield Formation of Claiborne Group. The Wilcox aquifer, located in northeastern and southern Arkansas, is composed of Paleocene-age sand beds found in the middle to lower part of the Wilcox Group. The Cockfield and Wilcox aquifers are primary sources of groundwater. In 2010, withdrawals from the Cockfield aquifer in Arkansas totaled 19.2 million gallons per day (Mgal/d), and withdrawals from the Wilcox aquifer totaled 36.5 Mgal/d. A study was conducted by the U.S. Geological Survey in cooperation with the Arkansas Natural Resources Commission and the Arkansas Geological Survey to measure water levels associated with the Cockfield aquifer and the Wilcox aquifer in northeastern and southern Arkansas. Water levels were measured at 43 wells completed in the Cockfield aquifer and 47 wells completed in the Wilcox aquifer in February and March 2012. Measurements from 2012 are presented as potentiometric-surface maps and in combination with measurements from 2006 as water-level difference maps. Trends in water-level change over time within the Cockfield and Wilcox aquifers were determined using the water-level difference maps and selected well hydrographs. The Cockfield aquifer study area in southern Arkansas is bounded on the east by the Mississippi River and on the west by the area that contains outcrops and subcrops of the Cockfield Formation. The northern boundary of the Cockfield aquifer study area is defined by the area that contains observation wells completed in the Cockfield aquifer and the southern boundary is the Louisiana State line. The Wilcox aquifer study area in northeastern Arkansas is bounded on the east by the Mississippi River and on the north by the Missouri State line. The southern and western boundaries are defined by areas containing observation wells completed in the Wilcox aquifer or by outcrop areas on or near Crowleys Ridge. The Wilcox aquifer study area in southern Arkansas is defined by observation wells completed in the Wilcox aquifer or by areas that contain outcrops of the Wilcox Group, or both. The potentiometric-surface map of the Cockfield aquifer shows the regional direction of groundwater flow was generally toward the east-southeast, except in areas of intense groundwater withdrawals such as southwestern Ashley County, where groundwater flows toward the town of Crossett. The highest water-level altitude measured was 350 feet (ft) above National Geodetic Vertical Datum of 1929 (NGVD 29) in central Columbia County. The lowest water-level altitude measured was 40 ft above NGVD 29 in southeastern Lincoln County. The water-level difference map for the Cockfield aquifer in Arkansas was constructed using 42 water-level measurements made during 2006 and 2012. The difference in water levels for the Cockfield aquifer ranged from 27.4 ft to -10.4 ft. The largest water-level rise was in Calhoun County, and the largest water-level decline was 10.4 ft in Union County. Of the 42 wells, 13 wells had a rise in water level, and the remaining 29 wells had a decline in water level. Hydrographs for 32 wells in the Cockfield aquifer with historical water-level data were evaluated using linear regression to calculate the annual rise or decline for each well. These data were aggregated by county and statistically evaluated for the range, mean, and median of water-level change in each county. Hydrographs for Bradley, Calhoun, Chicot, Columbia, and Union Counties indicated both rising and declining water levels. The mean annual water-level rise or decline for Calhoun County was 0.00 foot per year (ft/yr) or unchanged. The mean annual water-level for Ashley, Bradley, Chicot, Cleveland, Columbia, Lincoln, and Union Counties show declines ranging from -0.02 to -1.10 ft/yr. Two potentiometric-surface maps, one for the southern area and one for the northeastern area, were constructed to show the altitude of the water surface in the Wilcox aquifer. The direction of groundwater flow in the northeastern area was generally towards the south-southwest except for some areas immediately adjacent to the Mississippi River where the flow was more eastward towards the river. The highest water-level altitude was 219 ft in northern Mississippi County, and the lowest water-level altitude was 123 ft near West Memphis in Crittenden County. The direction of groundwater flow in the northern part of the southern area was generally towards the southwest. The direction of groundwater flow in the southern part was in all directions because of two cones of depression and two water-level mounds. The highest water-level altitude measured was 394 ft at the center of a water-level mound in eastern Hot Spring County and a water-level mound in southwestern Hempstead County. The lowest water-level altitude measured was 145 ft at the center of the cone of depression in Clark County. Water-level difference maps for the Wilcox aquifer in Arkansas were constructed using 47 water-level measurements made during 2006 and 2012. The difference in water levels for the Wilcox aquifer in the northeastern area ranged from 22.0 ft to -17.9 ft. The largest rise in water level occurred in Crittenden County, and the largest decline occurred in Lee County. Twenty-one wells had rising water levels, and 10 wells had declining water levels. The difference in water levels for the Wilcox aquifer in the southern area ranged from 18.1 ft to -4.2 ft. The largest rise and the largest decline in water level occurred in Nevada County. Twelve wells had rising water levels, and 4 wells had declining water levels. Linear regression analysis of long-term hydrographs was used to determine the mean annual water-level rise and decline in the Wilcox aquifer in the northeastern and southern areas of Arkansas. In the northeastern area, the mean annual water level declined in all seven counties. The mean annual declines ranged from -0.55 ft/yr in Craighead County to -1.46 ft/yr in St. Francis County. In the southern area, the annual rise and decline calculations for wells with over 20 years of records indicate rising and declining water levels in Clark, Hot Spring, and Nevada Counties. The mean annual water level declined in all counties except Hot Spring County.

Arkansas↗