In June of 2011, the U.S. Geological Survey acquired high-resolution P- and S-wave seismic data across the mapped (Schussler, 1906) trace of the San Andreas Fault zone at San Andreas Lake in unincorporated San Mateo County, California. Our seismic survey consisted of seismic reflection, refraction, and guided-wave data along a 60-m-long profile. To acquire the reflection and refraction data we co-located shots and geophones, spaced every meter along the profile. We used 59 SercelTM L40A, P-wave (40-Hz vertical-component) geophones (sensitivity of 22.34 volts/meter/second) to record 59 P-wave shots and 59 SercelTM L28-LBH, S-wave (4.5-Hz horizontal-component) geophones (sensitivity of 31.3 volts/meter/second)to record 59 S-wave shots. We generated P-wave data using a charge from a Betsy SeisgunTM, with the charge placed approximately 0.4 meters (16 inches) beneath the ground surface. The charge consisted of an 8-gauge, 400-grain, blank shotgun shell. S-wave sources were generated by horizontally striking an aluminum block with a 3.5-kg sledgehammer. We acquired fault-zone-guided-wave data using approximately one pound of explosives within a mapped trace of the San Andreas Fault, approximately 1.74 km NNW of the recording arrays. The explosives were placed in a 5-cm (2 inch) diameter borehole approximately 3-meter (10 feet) deep. All data were recorded using a 60-channel Geometrics Stratavisor NX-60TM seismograph with a 24-bit analog-to-digital converter and a roll-along descaling factor, and the output data are in SEG-Y format (Barry et al, 1975). Each in-line shot was recorded for two seconds, with data recording starting 100 ms before the actual time of the shot. Data were recorded at a sampling rate of 0.5 ms, or 2000 samples per second. This report provides the metadata needed to analyze the seismic data. References Barry, K.M., Cavers, D.A. and Kneale, C.W., 1975, Recommended standards for digital tape formats: Geophysics, vol. 40, no. 2, p. 344-352. Schussler, H., 1906, The Water Supply of San Francisco, California, Before, During, and After the Earthquake of April 18, 1906 and the Subsequent Conflagration: Martin B. Brown Press, New York, 103 pp.

In June of 2011, the U.S. Geological Survey acquired high-resolution P- and S-wave seismic data across the mapped (Schussler, 1906) trace of the San Andreas Fault zone at San Andreas Lake in unincorporated San Mateo County, California. Our seismic survey consisted of seismic reflection, refraction, and guided-wave data along a 60-m-long profile. To acquire the reflection and refraction data we co-located shots and geophones, spaced every meter along the profile. We used 59 SercelTM L40A, P-wave (40-Hz vertical-component) geophones (sensitivity of 22.34 volts/meter/second) to record 59 P-wave shots and 59 SercelTM L28-LBH, S-wave (4.5-Hz horizontal-component) geophones (sensitivity of 31.3 volts/meter/second)to record 59 S-wave shots. We generated P-wave data using a charge from a Betsy SeisgunTM, with the charge placed approximately 0.4 meters (16 inches) beneath the ground surface. The charge consisted of an 8-gauge, 400-grain, blank shotgun shell. S-wave sources were generated by horizontally striking an aluminum block with a 3.5-kg sledgehammer. We acquired fault-zone-guided-wave data using approximately one pound of explosives within a mapped trace of the San Andreas Fault, approximately 1.74 km NNW of the recording arrays. The explosives were placed in a 5-cm (2 inch) diameter borehole approximately 3-meter (10 feet) deep. All data were recorded using a 60-channel Geometrics Stratavisor NX-60TM seismograph with a 24-bit analog-to-digital converter and a roll-along descaling factor, and the output data are in SEG-Y format (Barry et al, 1975). Each in-line shot was recorded for two seconds, with data recording starting 100 ms before the actual time of the shot. Data were recorded at a sampling rate of 0.5 ms, or 2000 samples per second. This report provides the metadata needed to analyze the seismic data. References Barry, K.M., Cavers, D.A. and Kneale, C.W., 1975, Recommended standards for digital tape formats: Geophysics, vol. 40, no. 2, p. 344-352. Schussler, H., 1906, The Water Supply of San Francisco, California, Before, During, and After the Earthquake of April 18, 1906 and the Subsequent Conflagration: Martin B. Brown Press, New York, 103 pp.

In September 2021, the U.S. Geological Survey acquired high-resolution P- and S-wave data near seismic station CE.57213 in Fremont, California, approximately 100 m east of the mapped trace of the Hayward Fault. We acquired the seismic data to evaluate the time-averaged shear-wave velocity in the upper 30 m (VS30) and to better understand ground-shaking near the station CE.57213. The seismic data were acquired using a linear array of SmartSolo 3-component nodal seismometers (nodes), which continuously recorded at 2000 samples per second (0.5-ms sampling rate). We deployed 60 nodes, spaced at 2-m increments, along a 180-m-long, northeast-southwest-trending linear array. We generated P-wave seismic sources (shots) adjacent to each node at a 1-m offset using a 3.5-kg sledgehammer to vertically strike a steel plate on the ground surface. S-wave sources (shots) were generated adjacent to each node by horizontally striking an aluminum block with a 3.5-kg sledgehammer. For each shot point, we extracted approximately 2 seconds of data from each node following the shot times, combined the seismic traces into a single shot gather, and stored the data in SEG-Y format (Barry et al, 1975). This report provides the metadata needed to analyze the seismic data.

The U.S. Geological Survey acquired high-resolution P- and S-wave seismic data across the Frijoles Fault strand of the San Gregorio Fault Zone (SGFZ) at northern Año Nuevo, California in 2012. SGFZ is a right-lateral fault system that is mainly offshore, and prior studies provide highly variable slip estimates, which indicates uncertainty about the seismic hazard it poses. Therefore, the primary goal of the seismic survey was to better understand the structure and geometry of the onshore section of the Frijoles Fault strand of the SGFZ. We deployed 118 geophones (channels) at 5-m spacing along a linear profile centered on the mapped surface trace of the Frijoles Fault and co-located active P- and S-wave sources at ~1-m offset from the geophones. Channel numbers increase from west to east along the profile. We generated P-waves using either a seisgun (www.utep.edu/science/ssf/Manuals/betsy_seisgun.pdf, accessed August 2022) or an accelerated weight-drop and S-waves by horizontally striking an aluminum block on both sides with a sledgehammer. We first deployed vertical-component geophones (40-Hz, SercelTM L40A, sensitivity of 22.34 volts/meter/second) to record P-wave sources, after which we replaced the vertical-component geophones with horizontal-component geophones (4.5-Hz, SercelTM L28-LBH, sensitivity of 31.3 volts/meter/second) to record S-wave sources. Refraction cables connected all geophones to two 60-channel Geometrics Stratavisor NX-60TM seismographs with 24-bit analog-to-digital converters. Each shot was recorded at a 0.5-ms sampling rate for two seconds, with data recording at 100 ms before the actual time of the shot. This data release provides the metadata needed to utilize the seismic data. Data Format and Files We combined each seismic trace for a given shot time into a shot gather, and the traces in each shot gather are ordered by channel numbers (1-118) based on the position of the geophones along the profile. Furthermore, we assigned a unique field number (FFID) to each shot gather, and we combined the shot gathers recorded from both seismographs into two SEG-Y files (Barry et al., 1975), 78023.segy (channels 1 to 60) and marine.segy (channels 61 to 118), which are stored in big-Endian, 4-byte IBM-floating-point format (format code 1). Data samples are in millivolts and can be converted to velocity using the geophone sensitivity values. Metadata for all profiles are contained in two text files and one xml file: PIE12.setup.csv, PIE12.location.csv, and PIE12Metadata.xml. The setup file describes the identification of shots recorded by the two seismographs, channel number, recording stations (geophones), and the source type for both SEG-Y files. The location file describes the channel number, latitude, and longitude of all geophone locations. Reference Barry, K.M., Cavers, D.A., and Kneale, C.W., 1975, Recommended standards for digital tape formats: Geophysics, vol. 40, no. 2, p. 344-352, doi: 10.1190/1.1440530.

The U.S. Geological Survey acquired high-resolution P- and S-wave seismic data across the Frijoles Fault strand of the San Gregorio Fault Zone (SGFZ) at northern Año Nuevo, California in 2012. SGFZ is a right-lateral fault system that is mainly offshore, and prior studies provide highly variable slip estimates, which indicates uncertainty about the seismic hazard it poses. Therefore, the primary goal of the seismic survey was to better understand the structure and geometry of the onshore section of the Frijoles Fault strand of the SGFZ. We deployed 118 geophones (channels) at 5-m spacing along a linear profile centered on the mapped surface trace of the Frijoles Fault and co-located active P- and S-wave sources at ~1-m offset from the geophones. Channel numbers increase from west to east along the profile. We generated P-waves using either a seisgun (www.utep.edu/science/ssf/Manuals/betsy_seisgun.pdf, accessed August 2022) or an accelerated weight-drop and S-waves by horizontally striking an aluminum block on both sides with a sledgehammer. We first deployed vertical-component geophones (40-Hz, SercelTM L40A, sensitivity of 22.34 volts/meter/second) to record P-wave sources, after which we replaced the vertical-component geophones with horizontal-component geophones (4.5-Hz, SercelTM L28-LBH, sensitivity of 31.3 volts/meter/second) to record S-wave sources. Refraction cables connected all geophones to two 60-channel Geometrics Stratavisor NX-60TM seismographs with 24-bit analog-to-digital converters. Each shot was recorded at a 0.5-ms sampling rate for two seconds, with data recording at 100 ms before the actual time of the shot. This data release provides the metadata needed to utilize the seismic data. Data Format and Files We combined each seismic trace for a given shot time into a shot gather, and the traces in each shot gather are ordered by channel numbers (1-118) based on the position of the geophones along the profile. Furthermore, we assigned a unique field number (FFID) to each shot gather, and we combined the shot gathers recorded from both seismographs into two SEG-Y files (Barry et al., 1975), 78023.segy (channels 1 to 60) and marine.segy (channels 61 to 118), which are stored in big-Endian, 4-byte IBM-floating-point format (format code 1). Data samples are in millivolts and can be converted to velocity using the geophone sensitivity values. Metadata for all profiles are contained in two text files and one xml file: PIE12.setup.csv, PIE12.location.csv, and PIE12Metadata.xml. The setup file describes the identification of shots recorded by the two seismographs, channel number, recording stations (geophones), and the source type for both SEG-Y files. The location file describes the channel number, latitude, and longitude of all geophone locations. Reference Barry, K.M., Cavers, D.A., and Kneale, C.W., 1975, Recommended standards for digital tape formats: Geophysics, vol. 40, no. 2, p. 344-352, doi: 10.1190/1.1440530.

The updated 2018 National Seismic Hazard Model includes new ground motion models, aleatory uncertainty, and soil amplification factors for the central and eastern U.S. and incorporates basin depths from local seismic velocity models in four western U.S. (WUS) urban areas. These additions allow us, for the first time, to calculate probabilistic seismic hazard curves for an expanded set of spectral periods (0.01 s to 10 s) and site classes (VS30 = 150 m/s to 1,500 m/s) for the conterminous U.S. (CONUS), as well as account for amplification of long-period ground motions in deep sedimentary basins in the Los Angeles, San Francisco Bay, Salt Lake City, and Seattle regions. Ground motion data for 2, 5, and 10 percent probability of exceedance in 50 years have been derived from these hazard curves.Two sets of data are available: (1) 0.05 by 0.05 degree gridded hazard data for the CONUS and (2) 0.01 by 0.01 degree gridded hazard data for WUS basins. Note that both sets of data contain basin amplification in deep sedimentary basins in the WUS. The 0.01 degree by 0.01 degree data simply provides a higher resolution dataset than then 0.05 degree by 0.05 degree dataset. This dataset is discussed in the journal article titled: "The 2018 update of the US National Seismic Hazard Model: Additional period and site class data" by Shumway et al. (2021) located at https://doi.org/10.1177/8755293020970979. First Posted - October 7, 2019 Revised - February 2020 (ver 1.1) Revised - May 2021 (ver 1.2)

The updated 2018 National Seismic Hazard Model includes new ground motion models, aleatory uncertainty, and soil amplification factors for the central and eastern U.S. and incorporates basin depths from local seismic velocity models in four western U.S. (WUS) urban areas. These additions allow us, for the first time, to calculate probabilistic seismic hazard curves for an expanded set of spectral periods (0.01 s to 10 s) and site classes (VS30 = 150 m/s to 1,500 m/s) for the conterminous U.S. (CONUS), as well as account for amplification of long-period ground motions in deep sedimentary basins in the Los Angeles, San Francisco Bay, Salt Lake City, and Seattle regions. Ground motion data for 2, 5, and 10 percent probability of exceedance in 50 years have been derived from these hazard curves.Two sets of data are available: (1) 0.05 by 0.05 degree gridded hazard data for the CONUS and (2) 0.01 by 0.01 degree gridded hazard data for WUS basins. Note that both sets of data contain basin amplification in deep sedimentary basins in the WUS. The 0.01 degree by 0.01 degree data simply provides a higher resolution dataset than then 0.05 degree by 0.05 degree dataset. This dataset is discussed in the journal article titled: "The 2018 update of the US National Seismic Hazard Model: Additional period and site class data" by Shumway et al. (2021) located at https://doi.org/10.1177/8755293020970979. First Posted - October 7, 2019 Revised - February 2020 (ver 1.1) Revised - May 2021 (ver 1.2)

In November of 2021, the U.S. Geological Survey acquired high-resolution P- and S-wave seismic data at two seismic recording stations in Tulare and Fresno counties, California: Berkeley Digital Seismic Network BK.LIND and BK.KARE. We deployed 60 DTCC SmartSolo 3-component nodal seismometers (“nodes”) at 2-m intervals along a linear array at each seismic recording station. The nodes recorded seismic data continuously at a 0.5-ms sampling interval, and shot timing was recorded by GPS event capture hardware to precisely determine the shot times. We generated active-source P-waves by vertically striking a steel plate with a 3.5-kg sledgehammer, and active-source S-waves by horizontally striking an aluminum block with a 3.5-kg sledgehammer. The active-sources were generated at about 1-m offset from the nodes along the arrays.

In October 2016, we acquired an approximately 15-km-long seismic profile along a linear transect across the East Bay region of the San Francisco Bay area. Our goal was to image previously unknown strands of the Hayward Fault zone and to better delineate the structure and geometry of the main trace of the Hayward Fault. Our profile started near the southern border of San Leandro, California at the San Francisco Bay shoreline, trended ENE through the northern edge of Castro Valley, California, and ended approximately 5 km WSW of San Ramon, California. The data were analyzed using refraction tomography modeling, reflection processing, and guided-wave analysis. The analyzed data are presented in separate reports by Strayer and others (submitted to BSSA). The seismic data were generated at 26 shotpoints: 16 shotpoints located along the profile (inline shotpoints) and 10 shotpoints offset from the profile and located within known or suspected fault traces (guided-wave shotpoints). Most shotpoints used explosive sources to generate the seismic waves, but three of the shotpoints used repeated hits from a 227-kg (500 lb) accelerated weight dropped ~2 feet above a steel plate to generate the seismic signal. Data from each shot were recorded by a total of 459 seismographs, mostly deployed along the profile at intervals ranging from 20 to 100 meters. This data release contains the raw field records from all explosive and weight drop shots. The raw field records are in a proprietary Trimble TRD format and consist of continuous seismograph recordings during the time of the data collection. Also included in this data release are multiple SEG-Y files consisting of thirty-second-long traces "cut" from the TRD files and resorted into conventional shot gathers. These data are in standard SEG-Y format, with the data samples in IBM floating point format. Data samples are in units of meters/second, without filtering or other data manipulation.

In October 2016, we acquired an approximately 15-km-long seismic profile along a linear transect across the East Bay region of the San Francisco Bay area. Our goal was to image previously unknown strands of the Hayward Fault zone and to better delineate the structure and geometry of the main trace of the Hayward Fault. Our profile started near the southern border of San Leandro, California at the San Francisco Bay shoreline, trended ENE through the northern edge of Castro Valley, California, and ended approximately 5 km WSW of San Ramon, California. The data were analyzed using refraction tomography modeling, reflection processing, and guided-wave analysis. The analyzed data are presented in separate reports by Strayer and others (submitted to BSSA). The seismic data were generated at 26 shotpoints: 16 shotpoints located along the profile (inline shotpoints) and 10 shotpoints offset from the profile and located within known or suspected fault traces (guided-wave shotpoints). Most shotpoints used explosive sources to generate the seismic waves, but three of the shotpoints used repeated hits from a 227-kg (500 lb) accelerated weight dropped ~2 feet above a steel plate to generate the seismic signal. Data from each shot were recorded by a total of 459 seismographs, mostly deployed along the profile at intervals ranging from 20 to 100 meters. This data release contains the raw field records from all explosive and weight drop shots. The raw field records are in a proprietary Trimble TRD format and consist of continuous seismograph recordings during the time of the data collection. Also included in this data release are multiple SEG-Y files consisting of thirty-second-long traces "cut" from the TRD files and resorted into conventional shot gathers. These data are in standard SEG-Y format, with the data samples in IBM floating point format. Data samples are in units of meters/second, without filtering or other data manipulation.