ALBERT

Description: Stress maps show the orientation of the current maximum horizontal stress (SHmax) in the earth's crust. Assuming that the vertical stress (SV) is a principal stress, SHmax defines the orientation of the 3D stress tensor; the minimum horizontal stress Shmin is than perpendicular to SHmax. In stress maps SHmax orientations are represented as lines of different lengths. The length of the line is a measure of the quality of data and the symbol shows the stress indicator and the color the stress regime. The stress data are freely available and part of the World Stress Map (WSM) project. For more information about the data and criteria of data analysis and quality mapping are plotted along the WSM website at http://www.world-stress-map.org. The stress map of Taiwan 2022 is based on the WSM database release 2016. However, all data records have been checked and we added a large number of new data from earthquake focal mechanisms from the national earthquake catalog and from publications. The total number of data records has increased from n=401 in the WSM 2016 to n=6,498 (4,234 with A-C quality) in the stress map of Taiwan 2022 The update with earthquake focal mechanims is even larger since another 1313 earthquake focal mechanism data records beyond the scale of this map have been added to the WSM database. The digital version of the stress map is a layered pdf file generated with GMT (Wessel et al., 2019). It also provide estimates of the mean SHmax orientation on a regular 0.1° grid using the tool stress2grid (Ziegler and Heidbach, 2019). Two mean SHmax orientations are estimated with search radii of r=25 and 50 km, respectively, and with weights according to distance and data quality. The stress map and data are available on the landing page at https://doi.org/10.5880/WSM.Taiwan2022 where further information is provided. The earthquake focal mechanism that are used for this stress map are provided by the Taiwan Earthquake Research Center (TEC) available at the TEC Data Center (https://tec.earth.sinica.edu.tw).

Description: This data set contains measurements of an underground hydraulic fracture experiment at Äspö Hard Rock Laboratory in May and June 2015. The experiment tested various injection schemes for rock fracture stimulation and monitored the resulting seismicity. The primary purpose of the experiment is to identify injection schemes that provide rock fracturing while reducing seismicity or at least mitigate larger seismic events. In total, six tests with three different injection schemes were performed in various igneous rock types. Both the injection process and the accompanied seismicity were monitored. For injection monitoring, the water flow and pressure are provided and additional tests for rock permeability. The seismicity was monitored in both triggered and continuous mode during the tests by high-resolution acoustic emission sensors, accelerometers and broadband seismometers. Both waveform data and seismicity catalogs are provided.