VAAGE, S., HAUGLAND, K. and UTHEIM, T. 1983, Signatures from Single Airguns, Geophysical Prospecting 31, 87-97.The far-field signatures from a comprehensive and systematic airgun pulse test have been analyzed. Empirical relations between the characteristic signature parameters and depth (5-12 m), pressure (lock137 bar = 1s13.7 MPa) and total chamber volume (0.65-9.5 1) have been derived. Also, the influence of using waveshape kits in different positions within the chamber has been tested.The results indicate that:(1) The amplitude is proportional to chamber pressure to the power 3/4.(2) The bubble period is nearly independent of the position of the waveshape plate.(3) The increase in primary/bubble amplitude ratio is inversely proportional to the chamber volume above the waveshape plate.(4) The amplitude is independent of airgun depth.

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<p>The European Plate Observing System (EPOS) has established a pan-European infrastructure for solid Earth science data, governed by EPOS ERIC (European Research Infrastructure Consortium). The EPOS-Norway project is funded by the Research Council of Norway (Project no. 245763). The aim of the Norwegian EPOS e‑infrastructure is to integrate data from the Norwegian seismological and geodetic networks, as well as the data from the geological and geophysical data repositories.</p><p>We present the EPOS-Norway Portal as an online, open access, interactive tool, allowing visual analysis of multidimensional data. Currently it is providing access to more than 150 datasets (and growing) from four subdomains of Earth science in Norway. Those can be combined with your own data.</p><p>The EPOS-N Portal is implemented using Enlighten-web, a web program developed by NORCE. Enlighten-web facilitates interactive visual analysis of large multidimensional data sets. The Enlighten-web client runs inside a web browser. The user can create layouts consisting of one or more plots or views. Supported plot types are table views, scatter plots, vector plots, line plots and map views. For the map views the CESIUM framework is applied. Multiple scatter plots can be mapped on top of these map views.</p><p>An important element in the Enlighten-web functionality is brushing and linking, which is useful for exploring complex data sets to discover correlations and interesting properties hidden in the data. Brushing refers to interactively selecting a subset of the data. Linking involves two or more views on the same data sets, showing different attributes. The views are linked to each other, so that selecting a subset in one view automatically leads to the corresponding subsets being highlighted in all other linked views. If the updates in the linked plots are close to real-time while brushing, the user can perceive complex trends in the data by seeing how the selections in the linked plots vary depending on changes in the brushed subset. This interactivity requires GPU acceleration of the graphics rendering. In Enlighten-web, this is realized by using WebGL.</p><p>The EPOS-N Portal is accessing the external Granularity Database (GRDB) for metadata handling. Metadata can e.g. specify data sources, services, ownership, license information and data policy. Bar charts can be used for faceted search in metadata, e.g. search by categories. EPOS-N Portal can access remote datasets via web services. Relevant web services include FDSNWS for seismological data and OGC services for geological and geophysical data (e.g. WMS – Web Map Services). Standalone datasets are available through preloaded data files. Users can also simply add another WMS server or upload their own dataset for visualization.</p><p>Enlighten–web will also be adapted as a pilot ICS-D (Integrated Core Services - Distributed) for visualization in the European infrastructure. The EPOS ICS-C (Integrated Core Services - Central) is the entry point for users for accessing the e-Infrastructure under EPOS ERIC. ICS-C will let users create and manage workflows that usually include accessing data and services located in the EPOS Thematic Core Services (TCS).  The ICS-C and TCSs will be extended with additional computing facilities through the ICS-D concept.</p>

<p>The European Plate Observing System (EPOS) is a European project about building a pan-European infrastructure for accessing solid Earth science data, governed now by EPOS ERIC (European Research Infrastructure Consortium). The EPOS-Norway project (EPOS-N; RCN-Infrastructure Programme - Project no. 245763) is a Norwegian project funded by National Research Council. The aim of the Norwegian EPOS e‑infrastructure is to integrate data from the seismological and geodetic networks, as well as the data from the geological and geophysical data repositories. Among the six EPOS-N project partners, four institutions are providing data – University of Bergen (UIB), - Norwegian Mapping Authority (NMA), Geological Survey of Norway (NGU) and NORSAR.</p><p>In this contribution, we present the EPOS-Norway Portal as an online, open access, interactive tool, allowing visual analysis of multidimensional data. It supports maps and 2D plots with linked visualizations. Currently access is provided to more than 300 datasets (18 web services, 288 map layers and 14 static datasets) from four subdomains of Earth science in Norway. New datasets are planned to be integrated in the future. EPOS-N Portal can access remote datasets via web services like FDSNWS for seismological data and OGC services for geological and geophysical data (e.g. WMS). Standalone datasets are available through preloaded data files. Users can also simply add another WMS server or upload their own dataset for visualization and comparison with other datasets. This portal provides unique way (first of its kind in Norway) for exploration of various geoscientific datasets in one common interface. One of the key aspects is quick simultaneous visual inspection of data from various disciplines and test of scientific or geohazard related hypothesis. One of such examples can be spatio-temporal correlation of earthquakes (1980 until now) with existing critical infrastructures (e.g. pipelines), geological structures, submarine landslides or unstable slopes.  </p><p>The EPOS-N Portal is implemented by adapting Enlighten-web, a server-client program developed by NORCE. Enlighten-web facilitates interactive visual analysis of large multidimensional data sets, and supports interactive mapping of millions of points. The Enlighten-web client runs inside a web browser. An important element in the Enlighten-web functionality is brushing and linking, which is useful for exploring complex data sets to discover correlations and interesting properties hidden in the data. The views are linked to each other, so that highlighting a subset in one view automatically leads to the corresponding subsets being highlighted in all other linked views.</p>