Totally about 110 sites will be selected in the Upper Mississippi Embayment. Broadband station will be installed at each site. Also P- and S-wave seismic reflection/refraction profile will be conducted at each selected site. Broadband installation will be grouped into 15 sites (or as many as possible) at one time to record local, regional and teleseismic earthquakes for a period from a few days to a few months. Once there are a few earthquakes with good quality of waveforms recorded, they will be relocated to the next 15 stations. Each 15 stations will be deployed as an array to detect mid to lower crust arrivals from local and regional earthquakes.