Wideband Versus Broadband Seismic Sensors in Local and Regional Seismicity Monitoring

Session: Recent Advances in Very Broadband Seismology [Poster]
Type: Poster
Date: 4/30/2020
Time: 08:00 AM
Room: Ballroom
Description: 

A key question in geophysics is “Which sensor to choose?”, although the answer to this question is almost always “A broadband sensor,” a proper answer should be given based on user specific criteria. For example, local earthquakes do not produce low frequency energy, thus if the user is interested in local events she could avoid the use of expensive broadband seismometers. Low frequency geophones have been used in the past for this type of monitoring, however their response is typically very limited below 2Hz, and thus a magnitude overestimation may occur. Wide band seismic sensors (10sec-100Hz) are a cheap alternative to broad band sensors and are typically used in local and regional seismicity monitoring, however it is not always clear what are the achievable measurement levels and how these compare to sensors that are a lot more expensive. This work is a comparative study among three seismic sensors, a broad-band, a wide-band and a short-period, representing the state of the art in the market today. Two earthquakes with magnitudes M_L 4.9 & 4.7 at epicentral distances of 200km and 100km respectively, are analysed. The events have been recorded by colocated sensors and data are compared using spectrum plots of each channel. It is shown that despite the cost differences, wideband sensors provide identical performance compared to broadband sensors in the range of their recording spectrum, with no loss of any low period information. Coupled with the cost differences that allow more stations to be installed, it is made clear that the use of wideband sensors is the recommended way to go for local and regional seismicity as well as micro-seismicity monitoring.

Presenting Author: Nikos Germenis

Authors