Abstract

We introduce a new method to use narrowband regional amplitude envelopes for event analysis. Building on the success of the coda‐wave method, we construct synthetic template envelopes that attempt to fit the entire waveform, including multiple direct phases and their coda, across a broad frequency band. The method makes use of our understanding of earthquake and explosion source models, regional wave propagation, and the relationship between direct amplitudes and their respective codas. We demonstrate the power of the method by examining earthquake and nuclear explosions in the Korean Peninsula at regional distance stations MDJ (Mudangjing, China) and TJN (Taejon, South Korea). In order to implement the method, however, we need to account for propagation through the use of an attenuation model for the region, which we have developed, in addition to an empirical correction to provide for unaccounted effects in the direct‐to‐coda transfer functions. Under the assumption that our explosion and attenuation models and the empirically obtained P‐to‐P‐coda and S‐to‐S‐coda transfer functions are correct, we determine that the 2006 test by the Democratic People’s Republic of Korea (DPRK) is consistent with a yield between 200 and 800 tons and a depth between 20 and 300 m, with our best fit at 500 tons at a depth of 100 m. Similarly, the 2009 DPRK test is consistent with a yield range of 1–5 kt and a depth range of 70–600 m, with our best fit at 2 kt at a depth of 200 m.

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