THE NEW ENGLAND SEISMIC NETWORK (NESN)

HAGERTY, M. T., and EBEL, J. E., Weston Observatory, Boston College, Weston, MA 02493, hagertmb@bc.edu.

Weston Observatory operates an 11-station regional seismic network to monitor earthquake activity in New England (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont) and surrounding regions, with the purpose of compiling a complete catalog of earthquake activity in New England, assessing potential for future damaging earthquakes, and constraining patterns of strong ground motion for earthquakes in the region. Five of the stations were upgraded with broadband, 24-bit, continuously transmitting digitizers in 2003, and another five were upgraded in 2004. In 2005, station TRY at Rensselaer Polytechnic Institute (RPI) in Troy, NY, was reactivated. We plan to install five new broadband stations in Vermont, New Hampshire, and Maine in 2006 and an additional five sites in 2007. Further, we are working to incorporate strong motion data streams into our regional monitoring, both from strong motion stations that we will install, and from already existing urban monitoring installations. Our goal is to monitor earthquake activity in New England to as low a magnitude as possible; we estimate our current magnitude monitoring threshold to be about M2.5 for all of New England, and as low as M2.0 for southern New England. In addition, we have found that the seismicity of New England has a non-Poissonian pattern and this information is used to make short-term earthquake probability forecasts for New England which are available on our web site (http://www.bc.edu/westonobservatory).

Broadband, continuous data from our remote sites is transmitted to an Earthworm server at Weston Observatory, where a wavelet-transform (WT) based algorithm and identifier is used to automatically detect, classify and locate events and to notify observatory staff through an automatic paging system. This method has proved very successful at detecting and identifying local and regional events, quarry blasts, and teleseisms. Recently we implemented a new regional earthquake and blast associator which utilizes Lg travel times, and a new teleseism associator which has successfully located several teleseisms by fitting a plane wave to the observed slowness vector across the network. We are currently working to automate routine production of shake maps for the region.