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At least 55 records · Page 3Linked to original sources
USGS2007

Drying of floodplain forests associated with water-level decline in the Apalachicola River, Florida: Interim results, 2006

Floodplain forests of the Apalachicola River, Florida, are drier in composition today (2006) than they were before 1954, and drying is expected to continue for at least the next 50 years. Drier forest composition is probably caused by water-level declines that occurred as a result of physical changes in the main channel after 1954 and decreased flows in spring and summer months since the 1970s. Forest plots sampled from 2004 to 2006 were compared to forests sampled in the late 1970s (1976-79) using a Floodplain Index (FI) based on species dominance weighted by the Floodplain Species Category, a value that represents the tolerance of tree species to inundation and saturation in the floodplain and consequently, the typical historic floodplain habitat for that species. Two types of analyses were used to determine forest changes over time: replicate plot analysis comparing present (2004-06) canopy composition to late 1970s canopy composition at the same locations, and analyses comparing the composition of size classes of trees on plots in late 1970s and in present forests. An example of a size class analysis would be a comparison of the composition of the entire canopy (all trees greater than 7.5 cm (centimeter) diameter at breast height (dbh)) to the composition of the large canopy tree size class (greater than or equal to 25 cm dbh) at one location. The entire canopy, which has a mixture of both young and old trees, is probably indicative of more recent hydrologic conditions than the large canopy, which is assumed to have fewer young trees. Change in forest composition from the pre-1954 period to approximately 2050 was estimated by combining results from three analyses. The composition of pre-1954 forests was represented by the large canopy size class sampled in the late 1970s. The average FI for canopy trees was 3.0 percent drier than the average FI for the large canopy tree size class, indicating that the late 1970s forests were 3.0 percent drier than pre-1954 forests. The change from the late 1970s to the present was based on replicate plot analysis. The composition of 71 replicate plots sampled from 2004 to 2006 averaged 4.4 percent drier than forests sampled in the late 1970s. The potential composition of future forests (2050 or later) was estimated from the composition of the present subcanopy tree size class (less than 7.5 cm and greater than or equal to 2.5 cm dbh), which contains the greatest percentage of young trees and is indicative of recent hydrologic conditions. Subcanopy trees are the driest size class in present forests, with FIs averaging 31.0 percent drier than FIs for all canopy trees. Based on results from all three sets of data, present floodplain forests average 7.4 percent drier in composition than pre-1954 forests and have the potential to become at least 31.0 percent drier in the future. An overall total change in floodplain forests to an average composition 38.4 percent drier than pre-1954 forests is expected within approximately 50 years. The greatest effects of water-level decline have occurred in tupelo-cypress swamps where forest composition has become at least 8.8 percent drier in 2004-06 than in pre-1954 years. This change indicates that a net loss of swamps has already occurred in the Apalachicola River floodplain, and further losses are expected to continue over the next 50 years. Drying of floodplain forests will result in some low bottomland hardwood forests changing in composition to high bottomland hardwood forests. The composition of high bottomland hardwoods will also change, although periodic flooding is still occurring and will continue to limit most of the floodplain to bottomland hardwood species that are adapted to at least short periods of inundation and saturation.

Florida↗
USGS2022

Small anthropogenic landforms from past charcoal production control moisture dynamics and chemistry in northcentral Appalachian soils

Throughout the northeastern United States (U.S.) and Europe, relict charcoal hearths (RCHs) are regularly being discovered in proximity to furnaces once used for the extraction of metal from ore or quick-lime production; charcoal produced in hearths was used as a furnace fuel. Given previous research has shown that topographic and subsurface disturbance can be great when a hearth is constructed, we hypothesize that hearth construction alters surface hydrology and soil chemistry in environments in and near hearths. We used a landscape classification process to identify 6,758 hearths near furnaces at Greenwood and Pine Grove Furnace State Park, central and southcentral Pennsylvania, U.S. Two types of digital elevation model wetness indexes were used to quantify surface hydrology effects in and around hearths. Modeled wetness conditions were compared to field soil volumetric water content in RCHs near Greenwood Furnace State Park. Modeled wetness indexes indicate that RCH interiors are significantly wetter than RCH rim areas; RCHs are acting as a landscape moisture sink. Results also indicate that RCHs on slopes result in downslope drier conditions below RCHs. Field measured volumetric water content indicates that as distance from the center of the hearth increases, soil moisture significantly decreases. Geomorphic position was found to not be related to RCH wetness. Soil from RCHs, compared to nearby native soils, has significantly higher total C, a lower Mehlich 3 extractable acidity, higher Ca and P. No trend was evident with RCH soil chemistry and geomorphic position. The high frequency of RCH occurrence, in proximity to the furnace’s RCHs supported, suggests that RCHs today could locally be an important niche for understory flora and fauna. Further research could explore how RCHs might be affecting surrounding plant populations and how within RCH patterns, especially on hillslopes, might represent a distinctly different scale of physical and chemical variability.

Pennsylvania↗
USGS2020

Planktic foraminiferal test size and weight response to the late Pliocene environment

Atmospheric carbon dioxide ( p CO 2 atm ) is impacting the ocean and marine organisms directly via changes in carbonate chemistry and indirectly via a range of changes in physical parameters most dominantly temperature. To assess potential impacts of climate change on carbonate production in the open ocean, we measured size and weight of planktic foraminifers during the late Pliocene at p CO 2 atm concentrations comparable to today and global temperatures 2 to 3 °C warmer. Size of all foraminifers was measured at Atlantic Ocean Deep Sea Drilling Project (DSDP) Site 610, Ocean Drilling Program (ODP) Site 999, and Integrated Ocean Drilling Program (IODP) Site U1313. Test size was smaller during the Pliocene than in modern assemblages under the same environmental conditions. During the cold marine isotope stage (MIS) M2, size increased at Site 999, potentially linked to intensified stratification of the surface ocean in response to the closure of the Central American Seaway. At Site U1313, test size tracks the warming throughout the late Pliocene. Size-normalized weight (SNW) of Globigerina bulloides at Site U1313 decreased during warmer temperature intervals. SNW of Globigerinoides ruber (white) at Site 999 displays high-frequency variability not correlated to temperature. Yet during the glacial period within MIS M2, test weight was higher during higher temperatures. Our results support studies in the modern ocean, which challenge the view that carbonate chemistry is the primary driver for calcification. To better understand processes driving changes in SNW, computer tomography was used to quantify calcite to volume ratios. During interglacial periods, lower calcite volume but higher test volume suggests less suitable conditions for calcification. As this signal is not evident in SNW, subtle changes in calcification might not be observed by the weight-based method.

Paleoceanography and Paleoclimatology↗
USGS2010

Assessment and management of ecological integrity: Chapter 12

Assessing and understanding the impacts of human activities on aquatic ecosystems has long been a focus of ecologists, water resources managers, and fisheries scientists. While traditional fisheries management focused on single-species approaches to enhance fish stocks, there is a growing emphasis on management approaches at community and ecosystem levels. Of course, as fisheries managers shift their attention from narrow (e.g., populations) to broad organizational scales (e.g., communities or ecosystems), ecological processes and management objectives become more complex. At the community level, fisheries managers may strive for a fish assemblage that is complex, persistent, and resilient to disturbance. Aquatic ecosystem level objectives may focus on management for habitat quality and ecological processes, such as nutrient dynamics, productivity, or trophic interactions, but a long-term goal of ecosystem management may be to maintain ecological integrity. However, human users and social, economic, and political demands of fisheries management often result in a reduction of ecological integrity in managed systems, and this conflict presents a principal challenge for the modern fisheries manager. The concepts of biotic integrity and ecological integrity are being applied in fisheries science, natural resource management, and environmental legislation, but explicit definitions of these terms are elusive. Biotic integrity of an ecosystem may be defined as the capability of supporting and maintaining an integrated, adaptive community of organisms having a species composition, diversity, and functional organization comparable to that of a natural habitat of the region (Karr and Dudley 1981). Following that, ecological integrity is the summation of chemical, physical, and biological integrity. Thus, the concept of ecological integrity extends beyond fish and represents a holistic approach for ecosystem management that is especially applicable to aquatic systems. The more general term, ecological condition, refers to the state of the physical, chemical, and biological characteristics of the environment and the processes and interactions that connect them. While the concept of ecological integrity may appear unambiguous, its assessment and practice are much less clear. Ecological integrity made its debut in the USA with the Clean Water Act (CWA) of 1972 (Federal Water Pollution Control Act, as amended through Public Law 107–303, November 27, 2002), which states only one objective, “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.” This legislation compelled resource managers to focus on chemical pollution from point effluent sources, such as industrial and municipal outflows, as well as give attention to diffuse, chronic, and watershed effects on ecological integrity. Further, the CWA allowed pursuit of restoration programs in degraded water bodies and catalyzed the science and practice of restoration ecology. The term ecosystem health is often raised in discussions of ecological integrity. Perhaps it is natural to anthropomorphize our concern for personal health to ecosystems, so it becomes a useful metaphor for understanding the concept of ecological integrity. However, whether or not an ecosystem should be considered an entity, such as a superorganism, is a debate without end that began with early ecologists and continues today (Clements 1916; Suter 1993; Simon 1999a). Regardless, the ecosystem is indeed a natural unit with a level of organization and properties beyond the collection of those species that occupy it and presents the most appropriate spatial and organizational scale in which to assess and study ecological integrity. Streams and rivers serve as integrators of chemical, physical, and biological conditions across the landscape, and while the theory and practice associated with ecological integrity of aquatic systems is easily applied to flowing waters and is emphasized in this chapter, they are broadly applicable among all aquatic systems.

Book chapter↗
USGS2021

Geological constraints on the mechanisms of slow earthquakes

The recognition of slow earthquakes in geodetic and seismological data has transformed the understanding of how plate motions are accommodated at major plate boundaries. Slow earthquakes, which slip more slowly than regular earthquakes but faster than plate motion velocities, occur in a range of tectonic and metamorphic settings. They exhibit spatiotemporal associations with large seismic events that indicate a causal relation between modes of slip at different slip rates. Defining the physical controls on slow earthquakes is, therefore, critical for understanding fault and shear zone mechanics. In this Review, we synthesize geological observations of a suite of ancient structures that were active in tectonic settings comparable to where slow earthquakes are observed today. At inferred slow earthquake regions, a range of grain-scale deformation mechanisms accommodated slip at low effective stresses. Material heterogeneity and the geometric complexity of structures that formed at different inferred strain rates are common to faults and shear zones in multiple tectonic environments, and might represent key limiting factors of slow earthquake slip rates. Further geological work is needed to resolve how the spectrum of slow earthquake slip rates can arise from different grain-scale deformation mechanisms and whether there is one universal rate-limiting mechanism that defines slow earthquake slip.

Nature Reviews Earth and Environment↗
USGS2009

Guiding concepts for park and wilderness stewardship in an era of global environmental change

The major challenge to stewardship of protected areas is to decide where, when, and how to intervene in physical and biological processes, to conserve what we value in these places. To make such decisions, planners and managers must articulate more clearly the purposes of parks, what is valued, and what needs to be sustained. A key aim for conservation today is the maintenance and restoration of biodiversity, but a broader range of values are also likely to be considered important, including ecological integrity, resilience, historical fidelity (ie the ecosystem appears and functions much as it did in the past), and autonomy of nature. Until recently, the concept of “naturalness” was the guiding principle when making conservation‐related decisions in park and wilderness ecosystems. However, this concept is multifaceted and often means different things to different people, including notions of historical fidelity and autonomy from human influence. Achieving the goal of nature conservation intended for such areas requires a clear articulation of management objectives, which must be geared to the realities of the rapid environmental changes currently underway. We advocate a pluralistic approach that incorporates a suite of guiding principles, including historical fidelity, autonomy of nature, ecological integrity, and resilience, as well as managing with humility. The relative importance of these guiding principles will vary, depending on management goals and ecological conditions.

Frontiers in Ecology and the Environment↗
USGS2007

The role of fault zone drilling

The objective of fault-zone drilling projects is to directly study the physical and chemical processes that control deformation and earthquake generation within active fault zones. An enormous amount of field, laboratory, and theoretical work has been directed toward the mechanical and hydrological behavior of faults over the past several decades. Nonetheless, it is currently impossible to differentiate between – or even adequately constrain – the numerous conceptual models of active faults proposed over the years. For this reason, the Earth science community is left in the untenable position of having no generally accepted paradigm for the mechanical behavior of faults at depth. One of the primary causes for this dilemma is the difficulty of either directly observing or inferring physical properties and deformation mechanisms along faults at depth, as well as the need to observe directly key parameters such as the state of stress acting on faults at depth, pore fluid pressure (and its possible variation in space and time), and processes associated with earthquake nucleation and rupture. Today, we know very little about the composition of active faults at depth, their constitutive properties, the state of in situ stress or pore pressure within fault zones, the origin of fault-zone pore fluids, or the nature and significance of time-dependent fault-zone processes.

Book chapter↗
USGS2015

Assessing the geologic and climatic forcing of biodiversity and evolution surrounding the Gulf of California

For almost a century the Baja California peninsula (Peninsula), Gulf of California (Gulf), and broader Sonoran Desert region (figure 1) have drawn geologists and biologists alike to study its unique physical and evolutionary processes (e.g., Wittich 1920; Darton 1921; Nelson 1921; Johnston 1924; Beal 1948; Durham and Allison 1960). The challenge remains to untangle the long, intricate, and at times enigmatic geological and climatological histories that have shaped the high levels of endemism and biodiversity observed in the region today (Van Devender 1990; Grismer 2000; Riddle et al. 2000).

Gulf of California↗
USGS2023

Global seismic networks operated by the U.S. Geological Survey

The U.S. Geological Survey (USGS) Global Seismographic Network (GSN) Program operates two thirds of the GSN, a network of state‐of‐the‐art, digital seismological and geophysical sensors with digital telecommunications. This network serves as a multiuse scientific facility and a valuable resource for research, education, and monitoring. The other one third of the GSN is funded by the National Science Foundation (NSF), and the operations of this component are overseen by EarthScope. This collaboration between the USGS, EarthScope, and NSF has allowed for the development and operations of the GSN to be a truly multiuse network that provides near real‐time open access data, facilitating fundamental discoveries by the Earth science community, supporting the earthquake hazards mission of the USGS, benefitting tsunami monitoring by the National Oceanic and Atmospheric Administration, and contributing to nuclear test monitoring and treaty verification. In this article, we describe the installation and evolution of the seismic networks operated by the USGS that ultimately led to the USGS portion of the GSN (100 stations under network codes IU, IC, and CU) as they are today and envision technological advances and opportunities to further improve the utility of the network in the future. This article focuses on the USGS‐operated component of the GSN; a companion article on the GSN stations funded by the NSF and operated by the Cecil and Ida Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California at San Diego by Davis et al. (2023) appears in this volume.

Seismological Research Letters↗
USGS2024

Global assessment of aquatic Isoëtes species ecology

Isoëtes are iconic but understudied wetland plants, despite having suffered severe losses globally mainly because of alterations in their habitats. We therefore provide the first global ecological assessment of aquatic Isoëtes to identify their environmental requirements and to evaluate if taxonomically related species differ in their ecology. The assessment resulted in an extensive new database on aquatic Isoëtes , ecological niche analyses, and descriptive species accounts. We compiled a global database that includes all known environmental data collected from 1935 to 2023 regarding aquatic Isoëtes. We then evaluated the environmental drivers of 16 species using 2,179 global records. Additionally, we used hypervolume analysis to quantify the ecological niches of the two species with the greatest number of records, finding significant differences and evidence that Isoëtes echinospora occupies a wider ecological niche than Isoëtes lacustris . Fifty-nine species (30% of the c. 200 Isoëtes species known today) were categorised as aquatic and were mainly reported in the Americas and northern Europe. About 38% of the aquatic species are threatened with extinction or are endemic to a small region, according to the International Union for Conservation of Nature's Red List in 2023. Many species were determined to be sensitive to certain water physical and chemical factors, generally preferring oligotrophic conditions such as low total phosphorus, moderate total nitrogen, moderate to low pH, and low conductivity. This analysis includes ecological data in the assessment of rare/threatened aquatic plants globally. This new database and the ecological analyses completed defined the ecological requirements of several species and identified knowledge gaps, which can aid management actions and future research. This paper highlights ecological significance and environmental sensitivities of aquatic Isoëtes . The current level of knowledge is inadequate for a large proportion of known taxa. We affirm the extreme need to support global, collaborative initiatives on which to build future conservation strategies.

Freshwater Biology↗
USGS2023

A watershed moment for western U.S. dams

The summer of 2023 is a notable time for water-resource management in the western United States: Glen Canyon Dam, on the Colorado River, turns 60 years old while the largest dam-removal project in history is beginning on the Klamath River. This commentary discusses these events in the context of a changing paradigm for dam and reservoir management in this region. Since the era of large dam building began to wane six decades ago, new challenges have arisen for dam and reservoir management owing to climate change, population increase, reservoir sedimentation, declining safety of aging dams, and more environmentally focused management objectives. Today we also better understand dams' benefits, costs, and environmental impacts, including some that were unforeseen and took decades to become apparent. Where dams have become unsafe, obsolete (e.g., due to excessive reservoir sedimentation), and uneconomical beyond saving, dam removal has become common. The science and practice of dam removal are accelerating rapidly, and some long-term physical and biological response studies are now available. Removal of four hydroelectric dams on the Klamath River will be a larger and more complex project than any previous dam removal. The imminency of this project reflects a very different situation for dam and reservoir management than 60 years ago. Looking forward, dam and reservoir management in the western United States and worldwide will require continued collaboration and innovative thinking to meet a wide range of objectives and to manage water resources sustainably for future generations.

Water Resources Research↗
USGS2024

New insights on the origin of the Richardson-Richards equation

The Richardson-Richards equation (RRE), despite known shortcomings especially in regard to preferential flow, provides the basis of the vast majority of unsaturated flow models in use today. L.F. Richardson published this equation in 1922, nine years before L.A. Richards. Whereas Richards approached this problem directly from the groundbreaking developments of Edgar Buckingham, Richardson, surprisingly, cited as his starting point only the earlier work of L.J. Briggs. Collectively, these four scientists’ published and unpublished work reveals that: (1) Briggs’ work, though qualitative, captured the essential physical principles needed for quantifying unsaturated flow; (2) Buckingham came very close to deriving the RRE and explained why he stopped short of doing so; (3) derivation of the RRE from the work of either Briggs or Buckingham required only modest developmental work; and (4) besides deriving the RRE, Richards carried through much of the experimental agenda that Buckingham considered a necessary precursor to mathematical treatment.

Hydrological Sciences Journal↗
USGS2014

Debris flows: Behavior and hazard assessment

Debris flows are water-laden masses of soil and fragmented rock that rush down mountainsides, funnel into stream channels, entrain objects in their paths, and form lobate deposits when they spill onto valley floors. Because they have volumetric sediment concentrations that exceed 40 percent, maximum speeds that surpass 10 m/s, and sizes that can range up to ~109 m3, debris flows can denude slopes, bury floodplains, and devastate people and property. Computational models can accurately represent the physics of debris-flow initiation, motion and deposition by simulating evolution of flow mass and momentum while accounting for interactions of debris' solid and fluid constituents. The use of physically based models for hazard forecasting can be limited by imprecise knowledge of initial and boundary conditions and material properties, however. Therefore, empirical methods continue to play an important role in debris-flow hazard assessment.

Geology Today↗
USGS2013

Geomorphic and vegetation processes of the Willamette River floodplain, Oregon: current understanding and unanswered science questions

This report summarizes the current understanding of floodplain processes and landforms for the Willamette River and its major tributaries. The area of focus encompasses the main stem Willamette River above Newberg and the portions of the Coast Fork Willamette, Middle Fork Willamette, McKenzie, and North, South and main stem Santiam Rivers downstream of U.S. Army Corps of Engineers dams. These reaches constitute a large portion of the alluvial, salmon-bearing rivers in the Willamette Basin. The geomorphic, or historical, floodplain of these rivers has two zones - the active channel where coarse sediment is mobilized and transported during annual flooding and overbank areas where fine sediment is deposited during higher magnitude floods. Historically, characteristics of the rivers and geomorphic floodplain (including longitudinal patterns in channel complexity and the abundance of side channels, islands and gravel bars) were controlled by the interactions between floods and the transport of coarse sediment and large wood. Local channel responses to these interactions were then shaped by geologic features like bedrock outcrops and variations in channel slope. Over the last 150 years, floods and the transport of coarse sediment and large wood have been substantially reduced in the basin. With dam regulation, nearly all peak flows are now confined to the main channels. Large floods (greater than 10-year recurrence interval prior to basinwide flow regulation) have been largely eliminated. Also, the magnitude and frequency of small floods (events that formerly recurred every 2–10 years) have decreased substantially. The large dams trap an estimated 50–60 percent of bed-material sediment—the building block of active channel habitats—that historically entered the Willamette River. They also trap more than 80 percent of the estimated bed material in the lower South Santiam River and Middle and Coast Forks of the Willamette River. Downstream, revetments further decrease bed-material supply by an unknown amount because they limit bank erosion and entrainment of stored sediment. The rivers, geomorphic floodplain, and vegetation within the study area have changed noticeably in response to the alterations in floods and coarse sediment and wood transport. Widespread decreases have occurred in the rates of meander migration and avulsions and the number and diversity of landforms such as gravel bars, islands, and side channels. Dynamic and, in some cases, multi-thread river segments have become stable, single-thread channels. Preliminary observations suggest that forest area has increased within the active channel, further reducing the area of unvegetated gravel bars. Alterations to floods and sediment transport and ongoing channel, floodplain, and vegetation responses result in a modern Willamette River Basin. Here, the floodplain influenced by the modern flow and sediment regimes, or the functional floodplain, is narrower and inset with the broader and older geomorphic floodplain. The functional floodplain is flanked by higher elevation relict floodplain features that are no longer inundated by modern floods. The corridor of present- day active channel surfaces is narrower, enabling riparian vegetation to establish on formerly active gravel bar surfaces. The modern Willamette River Basin with its fundamental changes in the flood, sediment transport, and large wood regimes has implications for future habitat conditions. System-wide future trends probably include narrower floodplains and a lower diversity of landforms and habitats along the Willamette River and its major tributaries compared to historical patterns and today. Furthermore, specific conditions and future trends will probably vary between geologically stable, anthropogenically stable, and dynamic reaches. The middle and lower segments of the Willamette River are geologically stable, whereas the South Santiam and Middle Fork Willamette Rivers were historically dynamic, but are now largely stable in response to flow regulation and revetment construction. The upper Willamette and North Santiam Rivers retain some dynamic characteristics, and provide the greatest diversity of aquatic and riparian habitats under the current flow and sediment regime. The McKenzie River has some areas that are more dynamic, whereas other sections are stable due to geology or revetments. Historical reductions in channel dynamism also have implications for ongoing and future recruitment and succession of floodplain forests. For instance, the succession of native plants like black cottonwood is currently limited by (1) fewer low-elevation gravel bars for stand initiation; (2) altered streamflow during seed release, germination, and stand initiation; (3) competition from introduced plant species; and (4) frequent erosion of young vegetation in some locations because scouring flows are concentrated within a narrow channel corridor. Despite past alterations, the Willamette River Basin has many of the physical and ecological building blocks necessary for highly functioning rivers. Management strategies, including environmental flow programs, river and floodplain restoration, revetment modifications, and reclamation of gravel mines, are underway to mitigate some historical changes. However, there are some substantial gaps in the scientific understanding of the modern Willamette basin that is needed to efficiently integrate these blocks and to establish realistic objectives for future conditions. Unanswered questions include: 1. What is the distribution and diversity of landforms and habitats along the Willamette River and its tributaries? 2. What is the extent of today’s functional floodplain—the part of the river corridor actively formed and modified by fluvial processes? 3. How are landforms and habitats in the Willamette River Basin created and sustained by present-day flow and sediment conditions? 4. How is the succession of native floodplain vegetation shaped by present-day flow and sediment conditions? Answering these questions will produce baseline data on the current distributions of landforms and habitats (question 1), the extent of the functional floodplain (question 2), and the effects of modern flow and sediment regimes on future floodplain landforms, habitats, and vegetation succession (questions 3 and 4). Addressing questions 1 and 2 is a logical next step because they underlie questions 3 and 4. Addressing these four questions would better characterize the modern Willamette Basin and help in implementing and setting realistic targets for ongoing management strategies, demonstrating their effectiveness at the site and basin scales, and anticipating future trends and conditions.

Oregon↗
USGS1990

Perspectives on earthquake hazards in the New Madrid seismic zone, Missouri

A sequence of three great earthquakes struck the Central United States during the winter of 1811-1812 in the area of New Madrid, Missouri. they are considered to be the greatest earthquakes in the conterminous U.S because they were felt and caused damage at far greater distances than any other earthquakes in U.S history. The large population currently living within the damage area of these earthquakes means that widespread destruction and loss of life is likely if the sequence were repeated. In contrast to California, where the earthquakes are felt frequently, the damaging earthquakes that have occurred in the Easter U.S-in 155 (Cape Ann, Mass.), 1811-12 (New Madrid, Mo.), 1886 (Charleston S.C) ,and 1897 (Giles County, Va.- are generally regarded as only historical phenomena (fig. 1). The social memory of these earthquakes no longer exists. A fundamental problem in the Eastern U.S, therefore, is that the earthquake hazard is not generally considered today in land-use and civic planning. This article offers perspectives on the earthquake hazard of the New Madrid seismic zone through discussions of the geology of the Mississippi Embayment, the historical earthquakes that have occurred there, the earthquake risk, and the "tools" that geoscientists have to study the region. The so-called earthquake hazard is defined by the characterization of the physical attributes of the geological structures that cause earthquakes, the estimation of the recurrence times of the earthquakes, the estimation of the recurrence times of the earthquakes, their potential size, and the expected ground motions. the term "earthquake risk," on the other hand, refers to aspects of the expected damage to manmade strctures and to lifelines as a result of the earthquake hazard.

New Madrid seismic zone↗
USGS2018

U.S. Geological Survey response to white-nose syndrome in bats

Overview Since its discovery in 2007, the fungal disease known as white-nose syndrome (WNS) has killed more than six million bats. Ten of 47 bat species have been affected by WNS across 32 States and 5 Canadian Provinces. The cold-growing fungus ( Pseudogymnoascus destructans ) that causes WNS infects skin covering the muzzle, ears, and wings of hibernating bats. The fungus erodes deep into the vitally important skin of bat wings and fatally disrupts hibernation of bats through physical damage and energy depletion as they try to cope with infection. U.S. Geological Survey (USGS) science has been critical in identifying the causal fungus, characterizing the effects of WNS, and tracking the fungus as it rapidly spreads through many populations of bats in North America. Early USGS research enhanced our understanding of how WNS affects individual bats and how the fungus persists in the environment. Today, USGS scientists are engaged in a nationwide response to WNS, in close coordination with our partners at the U.S. Fish and Wildlife Service (USFWS), National Park Service (NPS), and U.S. Forest Service (USFS).

Fact Sheet↗
USGS2019

Deep convolutional neural networks for map-type classification

Maps are an important medium that enable people to comprehensively understand the configuration of cultural activities and natural elements over different times and places. Although a massive number of maps are available in the digital era, how to effectively and accurately locate and access the desired map on the Internet remains a challenge today. Previous works partially related to map-type classification mainly focused on map comparison and map matching at the local scale. The features derived from local map areas might be insufficient to characterize map content. To facilitate establishing an automatic approach for accessing the needed map, this paper reports our investigation into using deep learning techniques to recognize seven types of map, including topographic, terrain, physical, urban scene, the National Map, 3D, nighttime, orthophoto, and land cover classification. Experimental results show that the state-of-the-art deep convolutional neural networks can support automatic map-type classification. Additionally, the classification accuracy varies according to different map-types. This work can contribute to the implementation of deep learning techniques in the cartographic community and advance the progress of Geographical Artificial Intelligence (GeoAI).

Conference Paper↗
USGS2007

Grand Canyon Humpback Chub Population Improving

The humpback chub (Gila cypha) is a long-lived, freshwater fish found only in the Colorado River Basin. Physical adaptations-large adult body size, large predorsal hump, and small eyes-appear to have helped humpback chub evolve in the historically turbulent Colorado River. A variety of factors, including habitat alterations and the introduction of nonnative fishes, likely prompted the decline of native Colorado River fishes. Declining numbers propelled the humpback chub onto the Federal list of endangered species in 1967, and the species is today protected under the Endangered Species Act of 1973. Only six populations of humpback chub are currently known to exist, five in the Colorado River Basin above Lees Ferry, Ariz., and one in Grand Canyon, Ariz. The U.S. Geological Survey's Grand Canyon Monitoring and Research Center oversees monitoring and research activities for the Grand Canyon population under the auspices of the Glen Canyon Dam Adaptive Management Program (GCDAMP). Analysis of data collected through 2006 suggests that the number of adult (age 4+ years) humpback chub in Grand Canyon increased to approximately 6,000 fish in 2006, following an approximate 40-50 percent decline between 1989 and 2001. Increasing numbers of adult fish appear to be the result of steadily increasing numbers of juvenile fish reaching adulthood beginning in the mid- to late-1990s and continuing through at least 2002.

Fact Sheet↗