ALBERT

Description: Definitive digital values of the Earth's magnetic field recorded from 1991 to 2015 at INTERMAGNET observatories around the world. Data includes minute, hourly and daily vector values, along with observatory baseline values for quality control. Annual means are also included. All data is included on the single downloadable archive file (gzipped tar format) available from this landing page. This is the 25th annual publication in the series. Some national data institutions may have related DOIs that describe subsets of the data. These DOIs are shown under "Related DOIs to be quoted". For more information on the data formats used in this publication and the technical standards used to create the data, please refer to the INTERMAGNET Technical Manual and the Technical note TN6 "INTERMAGNET Definitive One-second Data Standard".

Description: This compilation contains definitive digital values of the Earth's magnetic field recorded from 1991 to 2016 at INTERMAGNET observatories around the world. Data includes minute, hourly and daily vector values, along with observatory baseline values for quality control. Annual means are also included. All data is included on the single downloadable archive file (gzipped tar format) available from this landing page. Beginning with the publication of the definitive data for 2015, INTERMAGNET stopped publishing individual years of data and started publishing the entire, cumulative definitive data set since INTERMAGNET’s first recorded definitive data in 1991. This data set is known as the "INTERMAGNET Reference Data Set" (IRDS). The IRDS comprises all INTERMAGNET one-minute definitive data since 1991 and is annually updated with a new year and occasional corrections to previous releases. Some national data institutions may have related DOIs that describe subsets of the data. These DOIs are shown under "Related DOIs to be quoted". File names for IRDS data are formatted in the form mag〈year〉_def〈year〉.zip. The mag〈year〉 section of the filename describes the year in which the data was recorded. The def〈year〉 section of the filename describes the most recent annual INTERMAGNET publication in which the data was updated. Files where mag〈year〉 = def〈year〉 have had no corrections since their original publication. For example, "mag2015_def2016" indicates that this file is different from the first release "mag2015_def2015". For more information on the data formats used in this publication and the technical standards used to create the data, please refer to the INTERMAGNET Technical Manual.

Description: The 100 km wide Mérida Andes extend from the Colombian/Venezuelan border to the Caribbean coast. To the north and south, the Mérida Andes are bound by hydrocarbon-rich sedimentary basins. This mountain chain and its associated major strike-slip fault systems formed by the oblique convergence of the Caribbean with the South American Plate and the north-eastwards expulsion of the North Andean Block in western Venezuela. In 2013, the Integrated Geoscience of the Mérida Andes Project (the GIAME project) was initiated to image the Mérida Andes on a lithospheric scale and to develop a dynamic model of their evolution by integrating wide-angle seismic, magnetotelluric and potential field data. Magnetotelluric (MT) dataset was acquired in 2015 along a 240 km long profile across the Mérida Andes. MT studies of orogens often reveal complex resistivity structures, typically associated with active deformation and characterized by high electrical conductivity zones. Fluids in fault systems and fluids derived from remineralization reactions of hydrous minerals often characterise high conductivity in active tectonic regimes. Cruces-Zabala et al. (2020) identified conductive zones with up to 10 km depth for the Maracaibo Basin and 5 km for the Barinas - Apure Basin. The Mérida Andes are charaterized by high resistivity separated by several conductive anomalies that corelate spatialy to the fault systems at the surface. A conductive zone a great depth (〉50km) was identified as a projection of the detachment surface of the Trujillo Block to the east. This data publication encompasses a detailed report in pdf format with a description of the project, information on the experimental setup, data collection, instrumentation used, recording configuration and data quality. The folder structure and content of the data repository are described in detail in Ritter et al. (2019). Time-series data are provided in EMERALD format (Ritter et al., 2015).

Description: This compilation contains definitive digital values of the Earth's magnetic field recorded from 1991 to 2017 at INTERMAGNET observatories around the world. Data includes minute, hourly and daily vector values, along with observatory baseline values for quality control. Annual means are also included. All data is included on the single downloadable archive file (gzipped tar format) available from this landing page. Beginning with the publication of the definitive data for 2015, INTERMAGNET stopped publishing individual years of data and started publishing the entire, cumulative definitive data set since INTERMAGNET’s first recorded definitive data in 1991. This data set is known as the "INTERMAGNET Reference Data Set" (IRDS). The IRDS comprises all INTERMAGNET one-minute definitive data since 1991 and is annually updated with a new year and occasional corrections to previous releases. Some national data institutions may have related DOIs that describe subsets of the data. These DOIs are shown under "Related DOIs to be quoted". File names for IRDS data are formatted in the form mag〈year〉_def〈year〉.zip. The mag〈year〉 section of the filename describes the year in which the data was recorded. The def〈year〉 section of the filename describes the most recent annual INTERMAGNET publication in which the data was updated. Files where mag〈year〉 = def〈year〉 have had no corrections since their original publication. For example, "mag2015_def2016" indicates that this file is different from the first release "mag2015_def2015". For more information on the data formats used in this publication and the technical standards used to create the data, please refer to the INTERMAGNET Technical Manual.

Description: Definitive digital values of the Earth's mangetic field recorded during 1991..2018 at INTERMAGNET observatories around the world. Data includes minute, hourly and daily vector values, along with observatory baseline values for quality control. Annual means are also included. All data is included on the single downloadable archive files. This is the 28th annual publication in the series. Beginning with the publication of the definitive data for 2015, INTERMAGNET stopped publishing individual years of data and started publishing the entire, cumulative definitive data set since INTERMAGNET’s first recorded definitive data in 1991. This data set is known as the "INTERMAGNET Reference Data Set" (IRDS). The IRDS comprises all INTERMAGNET one-minute definitive data since 1991 and is annually updated with a new year and occasional corrections to previous releases. Some national data institutions may have related DOIs that describe subsets of the data. These DOIs are shown under "Related DOIs to be quoted". File names for IRDS data are formatted in the form mag〈year〉_def〈year〉.zip. The mag〈year〉 section of the filename describes the year in which the data was recorded. The def〈year〉 section of the filename describes the most recent annual INTERMAGNET publication in which the data was updated. Files where mag〈year〉 = def〈year〉 have had no corrections since their original publication. For example, "mag2015_def2016" indicates that this file is different from the first release "mag2015_def2015". For more information on the data formats used in this publication and the technical standards used to create the data, please refer to the INTERMAGNET Technical Reference Manual. This mountain chain and its associated major strike-slip fault systems formed by the oblique convergence of the Caribbean with the South American Plate and the north-eastwards expulsion of the North Andean Block in western Venezuela. In 2013, the Integrated Geoscience of the Mérida Andes Project (the GIAME project) was initiated to image the Mérida Andes on a lithospheric scale and to develop a dynamic model of their evolution by integrating wide-angle seismic, magnetotelluric and potential field data. Magnetotelluric (MT) dataset was acquired in 2015 along a 240 km long profile across the Mérida Andes. MT studies of orogens often reveal complex resistivity structures, typically associated with active deformation and characterized by high electrical conductivity zones. Fluids in fault systems and fluids derived from remineralization reactions of hydrous minerals often characterise high conductivity in active tectonic regimes. Cruces-Zabala et al. (2020) identified conductive zones with up to 10 km depth for the Maracaibo Basin and 5 km for the Barinas - Apure Basin. The Mérida Andes are charaterized by high resistivity separated by several conductive anomalies that corelate spatialy to the fault systems at the surface. A conductive zone a great depth (〉50km) was identified as a projection of the detachment surface of the Trujillo Block to the east. This data publication encompasses a detailed report in pdf format with a description of the project, information on the experimental setup, data collection, instrumentation used, recording configuration and data quality. The folder structure and content of the data repository are described in detail in Ritter et al. (2019). Time-series data are provided in EMERALD format (Ritter et al., 2015).

Description: RST-Stick-Slipy is a software that analyzes the stick-slip characteristics of granular material tested with the ring shear tester RST.pc01 at the Helmholtz Tectonic Laboratory for Tectonic Modelling (HelTec). This software uses the time series created by the machine to automatically detect slip events and analyses several statistical properties depending on the type of test. Using the detected slip events the reloading stiffness and other properties such as recurrence times and stress drops are calculated. Further statistical properties such as the timing and stress level of slow and fast events are determined. Another segment of the module automatically analyses Slide-Hold-Slide experiments and determines the healing rate and other rate-and-state properties.

Description: This data set provides two series of experiments from ring-shear tests (RST) on glass beads that are in use at the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam. The main experimental series contains shear experiments to analyse the slip behaviour of the granular material under analogue experiment conditions. Additionally, a series of slide-hold-slide (SHS) tests was used to determine the rate and state friction properties. A basic characterisation and average friction coefficients of the glass beads are found in Pohlenz et al. (2020). The glass beads show a slip behaviour that is depending on loading rate, normal stress and apparatus stiffness which were varied systematically for this study. The apparatus was modified with springs resulting in 4 different stiffnesses. For each stiffness a set of 4 experiments with different normal stresses (5, 10, 15 and 20 kPa) were performed. During each experiment loading rate was decreased from 0.02 to 0.0008 mm/s resulting in 9 subsets of constant velocity for each experiment. We observe a large variety of slip modes that ranges from pure stick-slip to steady state creep. The main characteristics of these slip modes are the slip velocity and the ratio of slip event duration compared to no slip phases. We find that high loading rates promote stable slip, while low loading rates lead to stick-slip cycles. Lowering the normal stress leads to a larger amount of creep which changes the overall shape of a stick-slip curve and extends the time between slip events. Changing stiffness leads to an overall change in slip behaviour switching from simple stick-slip to more complex patterns of slip modes including oscillations and bimodal slip events with large and small events. The SHS tests were done at maximum stiffness and higher loading rates (〉0.05 mm/s) but at the same normal stress intervals as the main series. Using various techniques, we estimate the rate-and-state constitutive parameters. The peak stress after a certain amount of holding increases with a healing rate of b=0.0057±0.0005. From the increase in peak stress compared to the loading rate in slide-hold-slide tests we compute a direct effect a=-0.0076±0.0005 which leads to (a-b)=-0.0130±0.0006. Using a specific subset of the SHS tests, which have an equal ratio of hold time to reloading rate, we estimate (a-b)=-0.0087±0.0029. Both approaches show that the material is velocity weakening with a reduction in friction of 1.30 to 0.87 % per e-fold increase in loading rate. Additionally, the critical slip distance Dc is estimated to be in the range of 200 µm. With these parameters the theoretical critical stiffness kc is estimated and applied to the slip modes found in the main series. We find that the changes in slip mode are in good agreement with the estimated critical stiffness and thus confirm the findings from the SHS tests.

Description: Following a sequence of seismic events detected by the National Geographic Institute (IGN Spain), on 13.09.2021 the new volcano Cumbre Vieja initiated an eruption, located on the mid-western flank at a location just to the north of the 1949 eruption site. The eruption fed a lava flow that buried already some hundreds of houses, with a high economic estimated loss. Previous studies have shown that La Palma was the source of 3 or 4 large sector collapses associated with avalanches under see and tsunami generation. This volcanic activity is accompanied with an increased seismic activity. The GFZ contributes to the monitoring of the seismic activity by sending experts in the frame of a Hazard and Risk Team (HART). Our partner is the National Geographic Institute. Besides tiltmeters, a temporary 4 station seismic network with TrilliumCompact 20 sec posthole seismometers, D-Cube digitisers (100 sample/sec) and C-Cubes LTE communication for real-time data transmission is being deployed near the Cumbre Vieja volcano, increasing the station density of the IGN network. Data access is being restricted for some time.

Description: Convert and downsample distribute acoustic sensing (DAS) data acquired by Silixa iDAS or ASN OptoDAS to seismological data formats. Main purpose is to quickly convert and downsample massive amounts of high-resolution DAS data to MiniSEED and other seismological data formats. To handle the massive amount of data generated by DAS interrogators, the conversion tool is leveraging parallel I/O and multi-threaded signal-processing. A high throughput can be archived while converting and downsampling data in parallel threads. The tool can interact with tape storage systems and messaging bots to monitor the conversion process. The signal processing routines are based on Pyrocko, a mature and well tested seismological framework.