A U.S. seismologist who has studied seismic data associated with North Korea’s nuclear tests has been detained in China, according to reports. The case highlights how sensitive monitoring and research tied to the Korean Peninsula can become amid broader tensions between Washington and Beijing. Authorities have not publicly detailed the charges or timeframe for release. Supporters of the scientist say the work focuses on analyzing earthquakes and explosions using global monitoring networks. The detention is expected to complicate collaboration involving researchers in the region.