Network Facility is responsible for data collection from the Transportable Array stations. The Flexible Array is composed of 291 broadband stations, 120 short period stations, and 1700 active source stations. The Flexible Array allows sites to be targeted in a more focused manner than the broad Transportable Array. Natural or artificially created seismic waves can be used to map structures in the Earth. The Reference Network is composed of permanent seismic stations spaced about 300 km apart. The Reference Network provides a baseline for the Transportable Array and Flexible Array. EarthScope added and upgraded 39 stations to the already existing Advanced National Seismic System, which is part of the Reference Network. The Magnetotelluric Facility is composed of seven permanent and 20 portable sensors that record electromagnetic fields. It is the electromagnetic equivalent of the seismic arrays. The portable sensors are moved in a rolling grid similar to the Transportable Array grid, but are only in place about a month before they are moved to the next location. A magnetotelluric station consists of a magnetometer, four electrodes, and a data recording unit that are buried in shallow holes. The electrodes are oriented north-south and east-west and are saturated in a salt solution to improve conductivity with the ground. Plate Boundary Observatory (PBO) The Plate Boundary Observatory PBO consists of a series of geodetic instruments, Global Positioning System (GPS) receivers and borehole strainmeters, that have been installed to help understand the boundary between the North American Plate and Pacific Plate. The PBO network includes several major observatory components: a network of 1100 permanent, continuously operating Global Positioning System (GPS) stations many of which provide data at high-rate and in real-time, 78 borehole seismometers, 74 borehole strainmeters, 26 shallow borehole tiltmeters, and six long baseline laser strainmeters. These instruments are complemented by InSAR (interferometric synthetic aperture radar) and LiDAR (light detection and ranging) imagery and geochronology acquired as part of the GeoEarthScope initiative. PBO also includes comprehensive data products, data management and education and outreach efforts. These permanent networks are supplemented by a pool of portable GPS receivers that can be deployed for temporary networks to researchers, to measure the crustal motion at a specific target or in response to a geologic event. The Plate Boundary Observatory portion of EarthScope is operated by UNAVCO, Inc. UNAVCO is a non-profit, university-governed consortium that facilitates research and education using geodesy. San Andreas Fault Observatory at