MONITORING EXPLOSIONS
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The GSN/CDSN station MDJ near Mudanjiang, China, (red triangle) is about 370 km from the nuclear test site (yellow circle) of the Democratic people’s republic of Korea and is the closest station that provides open data in near-real time. At this distance, it is possible to see several features of regional seismic arrivals that help to discriminate between earthquakes and underground explosions.
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Earthquakes generate seismic waves but so do numerous other phenomena, including land- slides, mine collapses, underground explosions, ocean storms, and many human activities. Seismic data may be the only or best data to address a societal need to identify a source type, so investment continues in research and supporting infrastructure. Identification is more reliable when high quality broadband data are available from stations near and at different azimuths around the source, and if the properties of the crust and upper mantle are well known. Signals recorded by permanent stations installed at quiet sites and temporary stations deployed in denser arrays provide complementary information to continue improving seismic identification capabilities around the world.</p>