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TitleDiscriminating between low-magnitude shallow earthquakes and road construction blasts near Big Salmon River, New Brunswick, Canada
AuthorKolaj, M
SourceSeismological Research Letters vol. 89, no. 5, 2018 p. 1966-1976,
Alt SeriesNatural Resources Canada, Contribution Series 20180008
PublisherSeismological Society of America (SSA)
Mediapaper; on-line; digital
File formatpdf
ProgramCanadian Hazard Information Service
Released2018 06 20
AbstractSpectral ratio discriminants were developed to discriminate between low-magnitude (MN<2MN<2) shallow (depth <3km<3km) earthquakes and blasts related to road construction. The spectral ratios were formed from narrowband spectral?energy estimates between 1 and 40 Hz of Pg, Lg, and Rg for a total of 786 unique discriminants. From these discriminants, it was found that broadband high-frequency Pg/Lg and low?frequency Lg/Rg provided the largest separation between earthquakes and blasts. The high-frequency Pg/Lg spectral ratio confirms the applicability of P/S ratios for the discrimination of low-magnitude blasts from small local/regional shallow earthquakes. Furthermore, the success of the Lg/Rg spectral ratio demonstrates that the normalized Rg component from blasts typical of road construction projects tends to be larger at small epicentral distances (<50km<50km) than that of shallow earthquakes typical of the area. Although the results presented in this work were developed for a local area, the broader conclusions are likely expandable to other regions in Canada, in particular the Northern Appalachians, where discriminating between low-magnitude blasts related to mining and road construction and shallow earthquakes is a daily challenge.
Summary(Plain Language Summary, not published)
Discriminating between blasts (e.g., construction and mining) and earthquakes is a daily challenge in Canada. A particular example of this was near Big Salmon River in New Brunswick, Canada where both blasts (due to road construction) and earthquakes occurred in the same region. In this work, the ratios between specific seismic waves were shown to be able to discriminate between these two types of events and, based on these results, nine questionable events were reclassified to known blasts and one to a known earthquake.

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