GPS data serves as the basis for a geodetic model of the Alps. Here, a horizontal strain field is derived from the data. Red areas indicate compression; blue indicates lateral spreading. (Image: DGFI-TUM)
Our Earth is constantly on the move, as the current Kilauea eruption dramatically illustrates. But capturing data on small shifts over time isn’t so easy.
A new computer model based on more than a decade of GPS data shows the dynamic movements of the Alps as the mountain range drifts and rises.
In general, the range drifts an average of one-half millimeter and rises 1.8 millimeters every year.
However, there are strong regional variances. In South and East Tyrol, a rotation towards the east is superimposed on the overall movement, while at the same time the mountain range is being compressed. And the rise in height is not identical everywhere, either. While very small in the southern part of the western Alps, it reaches its maximum with a speed of more than 2 millimeters per year in the central Alps at the boundaries of Austria, Switzerland and Italy.
To create the model, researchers at the Technical University of Munich (TUM) German Geodetic Research Institute evaluated measurements made by more than 300 GPS antennas over a period of 12 years, in the German, Austrian, Slovenian, Italian, French and Swiss Alps. Over that time, each of the stations has been making positioning measurements every 15 seconds.
The team’s model makes the movements visible on a comprehensive basis for the first time.
The scientists identified the positions of the measurement stations, accurate down to fractions of a millimeter; many of the stations were set up in the EU project ALPS-GPSQUAKENET and are in part operated by TUM.
Once corrected for snow weight and atmospheric interference, the data show horizontal and vertical shifts as well as lateral spreading and compression at a resolution of 25 kilometers.
Explains Florian Seitz, chair of Geodetic Geodynamics, “The data are a goldmine for geodesy, with its objective of accurately measuring the surface of the Earth and identifying any changes occurring.”
The membership of the Open Geospatial Consortium (OGC) has approved GeoSciML as an OGC Standard. The OGC GeoSciML Standard defines a model and encoding for geological features commonly described and portrayed in geological maps, cross sections, geological reports and databases.
GeoSciML provides a mechanism for storage and exchange of a broad range of geologic data enabling users to generate geologic depictions (such as maps) in a consistent and repeatable fashion.
The model was developed by the IUGS CGI (Commission for the Management and Application of Geoscience Information), and version 4.1 is the first version officially submitted as an OGC standard. This standard describes a logical model and GML/XML encoding rules for geological map data, geological time scales, boreholes, and metadata for laboratory analyses.
“Earlier versions of GeoSciML have been used for several years by geological data sharing projects around the world when GeoSciML was only an IUGS (International Union of Geological Sciences) standard. These include OneGeology, INSPIRE, the US Geoscience Information Network (USGIN), and the Australian AuScope and AusGIN projects,” said Ollie Raymond, chair of the GeoSciML SWG.
“Having GeoSciML version 4 ratified as an official OGC standard is a huge step forward for GeoSciML, particularly to reassure application developers that GeoSciML is the way forward for geoscience data transfer,” Raymond said. “The collaboration of the previous IUGS GeoSciML working group and OGC has been a great example of effective cooperation between standards organisations.”
“The formal documentation and approval of the GeoSciML 4.1 standards by OGC allows us to expand the exchange of highly interoperable geoscience data throughout the South American continent with the support of the OneGeology standards support network and allowed us to achieve the maximum 5 stars of OneGeology interoperability,” said Maria Glícia da Nóbrega Coutinho. head of the International Affairs Office of CPRM (The Geological Survey of Brazil) and OneGeology Board representative for South America.
The GeoSciML standard includes a Lite model, used for simple map-based applications; a basic model, aligned with INSPIRE, for basic data exchange; and an extended model to address more complex scenarios. The standard also provides patterns, profiles (most notably of OGC Observations and Measurements; also ISO 19156), and best practices to deal with common geoscience use cases.
The Alaska Geologic Map shows the generalized geology of the state, each color representing a different type or age of rock. (Image: USGS)
A new digital geologic map of Alaska is being released today, providing land users, managers and scientists geologic information for the evaluation of land use in relation to resource extraction, conservation, natural hazards and recreation.
The U.S. Geological Survey (USGS) map gives visual context to the abundant mineral and energy resources found throughout the state in a detailed and accessible format.
“I am pleased that Alaska now has a state-wide digital map detailing surface geologic features of this vast region of the United States that is difficult to access,” said Suzette Kimball, newly confirmed director of the USGS. “This geologic map provides important information for the mineral and energy industries for exploration and remediation strategies. It will enable resource managers and land management agencies to evaluate resources and land use, and to prepare for natural hazards, such as earthquakes.”
“The data contained in this digital map will be invaluable,” said National Park Service Director Jonathan B. Jarvis. “It is a great resource and especially enhances the capacity for science-informed decision making for natural and cultural resources, interpretive programs, and visitor safety.”
“A better understanding of Alaska’s geology is vital to our state’s future. This new map makes a real contribution to our state, from the scientific work it embodies to the responsible resource production it may facilitate. Projects like this one underscore the important mission of the U.S. Geological Survey, and I’m thankful to them for completing it,” said Sen. Lisa Murkowski, R-Alaska.
This map is a completely new compilation, carrying the distinction of being the first 100 percent digital statewide geologic map of Alaska. It reflects the changes in our modern understanding of geology as it builds on the past. More than 750 references were used in creating the map, some as old as 1908 and others as new as 2015. As a digital map, it has multiple associated databases that allow creation of a variety of derivative maps and other products.
“This work is an important synthesis that will both increase public access to critical information and enhance the fundamental understanding of Alaska’s history, natural resources and environment,” said Mark Myers, Commissioner of Alaska’s Department of Natural Resources. “I applaud the collaborative nature of this effort, including the input provided by the Alaska Division of Geological and Geophysical Surveys, which will be useful for natural disaster preparation, resource development, land use planning and management, infrastructure and urban planning and management, education, and scientific research.”
Geologists and resource managers alike can utilize this latest geologic map of Alaska, and a lay person can enjoy the colorful patterns on the map showing the state’s geologic past and present.
More than other areas of the United States, Alaska reflects a wide range of past and current geologic environments and processes. The map sheds light on the geologic past and present. Today, geologic processes are still very important in Alaska with many active volcanoes, frequent earthquakes, receding and advancing glaciers and visible climate impacts.
“This map is the continuation of a long line of USGS maps of Alaska, reflecting ever increasing knowledge of the geology of the state,” said Frederic Wilson, USGS research geologist and lead author of the new map. “In the past, starting in 1904, geologic maps of Alaska were revised once a generation; this latest edition reflects major new mapping efforts in Alaska by the USGS and the Alaska state survey, as well as a revolution in the science of geology through the paradigm shift to plate tectonics, and the development of digital methods. Completion of this map celebrates the 200th anniversary of world’s first geologic map by William Smith of England in 1815.”
This map detail, of the Anchorage area, shows the city spread out on a plain of loose glacial deposits shown in yellow, and the bedrock making up the hillsides of Anchorage shown in green and brown. The rocks shown in green, called the Valdez Group, are sedimentary rocks formed in a trench 65 to 75 million years ago from thousands of undersea debris flows similar to the modern Aleutian trench where oceanic crust dives under continental crust (a subduction zone). The rocks shown in brown on the map are a chaotic mix of rock types called the McHugh Complex that were also formed about the same time, adjacent to this ancient subduction zone. Some time after deposition of the Valdez Group, hot fluids formed gold-bearing quartz veins; the veins were mined starting in the 1890’s. The rocks were pushed up, and attached (accreted) to North America through plate tectonic forces in the past 65 million years. The dotted line passing through the east side of Anchorage is the approximate trace of the Border Ranges Fault system, the boundary between the accreted rocks and the rest of the continent. This map detail, of the Anchorage area, shows the city spread out on a plain of loose glacial deposits shown in yellow, and the bedrock making up the hillsides of Anchorage shown in green and brown. The rocks shown in green, called the Valdez Group, are sedimentary rocks formed in a trench 65 to 75 million years ago from thousands of undersea debris flows similar to the modern Aleutian trench where oceanic crust dives under continental crust (a subduction zone). The rocks shown in brown on the map are a chaotic mix of rock types called the McHugh Complex that were also formed about the same time, adjacent to this ancient subduction zone. Some time after deposition of the Valdez Group, hot fluids formed gold-bearing quartz veins; the veins were mined starting in the 1890’s. The rocks were pushed up, and attached (accreted) to North America through plate tectonic forces in the past 65 million years. The dotted line passing through the east side of Anchorage is the approximate trace of the Border Ranges Fault system, the boundary between the accreted rocks and the rest of the continent. This map detail, of the Anchorage area, shows the city spread out on a plain of loose glacial deposits shown in yellow, and the bedrock making up the hillsides of Anchorage shown in green and brown. The rocks shown in green, called the Valdez Group, are sedimentary rocks formed in a trench 65 to 75 million years ago from thousands of undersea debris flows similar to the modern Aleutian trench where oceanic crust dives under continental crust (a subduction zone). The rocks shown in brown on the map are a chaotic mix of rock types called the McHugh Complex that were also formed about the same time, adjacent to this ancient subduction zone. Some time after deposition of the Valdez Group, hot fluids formed gold-bearing quartz veins; the veins were mined starting in the 1890’s. The rocks were pushed up, and attached (accreted) to North America through plate tectonic forces in the past 65 million years. The dotted line passing through the east side of Anchorage is the approximate trace of the Border Ranges Fault system, the boundary between the accreted rocks and the rest of the continent. (Image: USGS)
Map of sediment thickness in state waters offshore of San Francisco. About 21,000 years ago, sea level in this area was about 125 m lower and the shelf offshore San Francisco was an emergent land surface. At that time, the Sacramento River drained through the Golden Gate and eroded a valley (“the San Francisco paleovalley”) that was filled with sediment during subsequent sea-level rise. The thickest young sediment in the region occurs in the “San Andreas graben,” a basin that formed by crustal down dropping along the offshore section of the San Andreas fault. There is very little sediment on the shelf offshore of southern Ocean Beach (a pattern that extends south to Pescadero), a factor important for understanding and forecasting coastal erosion in this area.
Three new sets of maps detail the offshore bathymetry, habitats, geology and submarine environment of the seafloor off the coast of San Francisco, Drakes Bay and Tomales Point.
Critical for resource managers, the maps are part of the California Seafloor and Coastal Mapping Program, a series of maps published by the U.S. Geological Survey with support from the California Ocean Protection Council, NOAA and 15 other state and federal partners. The maps are designed to be used by a large stakeholder community and the public to manage and understand California’s vast and valuable marine resources.
“OPC is proud to be a partner in this interagency effort,” said California’s Secretary for Natural Resources and OPC Chair John Laird. “These maps are critical to the state’s innovative approach to coastal resource management. USGS’s products form the foundation for assessing the performance of our Marine Protected Area network and preparing for climate change impacts such as sea-level rise.”
“NOAA is pleased to be partnering in this integrated ocean and coastal mapping project. By working with partners from across federal, state, academic, and private sectors, we are able to combine data resources and maximize our efficiency in applying a ‘map once, use many times’ approach that benefits all,” said Rear Admiral Gerd F. Glang, director NOAA’s office of coast survey.
The program was initiated seven years ago with the goal of comprehensively surveying and mapping all of California’s state waters. The vision was tremendously ambitious — comparable mapping on this scale has not been attempted anywhere else in the world, the USGS said. Each of the three publications includes 10 map sheets, a pamphlet and a digital data catalog.
The maps and mapping data have a large range of applications. They provide:
a foundation for assessing marine protected areas and habitats;
baselines for monitoring coastal change and sea-level-rise impacts;
critical input data for modeling and mitigation of coastal flooding;
a framework for understanding coastal erosion and developing regional sediment management plans;
contributions to earthquake and tsunami hazard assessments;
more accurate maps for safer navigation;
and essential information for planning, siting, or removing offshore infrastructure.
The new “Offshore of San Francisco” maps document the complex submarine environments along the inlet to San Francisco Bay formed by strong tidal currents, including spectacular sand waves, a deep scour pool beneath the Golden Gate, and the dynamic offshore San Francisco mouth bar and “Potato Patch” shoal.
Sediment distribution maps reveal only a thin sediment cover offshore of the Ocean Beach (San Francisco) erosional hotspot (a pattern extending south to San Gregorio), indicating that today’s present coastal erosion will be a continuing problem, likely to be exacerbated by continuing sea-level rise.
Geologic maps incorporating subsurface data document the location and geometry of the San Andreas, San Gregorio and Point Reyes fault systems, and show how their interactions led to uplift of Point Reyes and development of a deep sediment-filled basin.
The Drakes Bay and Vicinity, and Offshore of Tomales Point maps reveal the diverse and complex range of seafloor habitats typical of the California coast, ranging from the rugged granitic bedrock along the high-energy west coast of Point Reyes, to smooth sand and mud in the more protected Drakes Bay environment that includes the Point Reyes State Marine Reserve.
“There is a ‘WOW!’ factor to the new high-resolution datasets and maps,” said Sam Johnson, the USGS project lead. “They’re allowing scientists to pose new questions and are having a significant role in stimulating research. We’re also seeing a positive impact on public education and awareness.”
To date, 12 map sets and catalogs have been published. Ten additional map sets are now being formatted for publication, which will complete coverage in the Santa Barbara Channel (Oxnard to Gaviota) and from Marina northward to beyond the Russian River.
The maps are created through the collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data.
Map of offshore sediment thickness in State Waters between Drakes Bay and Salt Point, north of the Russian River. The thickest sediment in the region occurs offshore of the Russian River, and in a large bar along the south flank of Point Reyes Head. There is a relative lack of offshore sediment between Bodega Head and Point Reyes, where the shelf is characterized by abundant rocky habitat and much of the coastal sediment is trapped in large onshore dune fields.Perspective view looking to the southeast over entrance to San Francisco Bay. Golden Gate Bridge is to left (east) of this view. The large sand-wave field lies within Golden Gate channel, and formed from sediment transported out of the Bay by strong tidal currents. Profile A–A’ shows that the larger bedforms can reach heights of over 7 m and are asymmetrical with steeper sides towards the open coast. A smaller field of sand waves to south near Baker Beach shows the opposite symmetry (steep sides toward the Bay) indicating that the strongest tidal currents in that local area are directed eastward.“Seafloor character” map of the San Francisco Region. This is a type of habitat map that classifies the seafloor based on surface hardness and roughness. Such maps are used in various types of ecosystem assessments and seafloor zoning, such as delineation or monitoring of marine protected areas.Bathymetry bounding Tomales Point. Rugged and massive granite outcrops extend offshore from Tomales Point to water depths of as much as 60 meters. Offshore sedimentary rock outcrops (lower left part of image) form distinctive “ribs” on the seafloor and have a notably different appearance. There is minimal sediment on this part of the California shelf because the watersheds draining the west flank of Tomales Point are very small and because Tomales Point and Tomales Bay block sediment transport from the north. Rocky-shelf outcrops and rubble are excellent habitats for rockfish and lingcod, recreationally and commercially important species. Tomales Bay, approximately 20-km long and 1- to 2-km wide, formed along a submerged portion of the San Andreas Fault (very shallow water depths preclude collection of high-resolution bathymetric data at the mouth of Tomales Bay).
