Japan Geoscience Union Meeting 2024

Presentation information

[J] Oral

H (Human Geosciences ) » H-CG Complex & General

[H-CG21] Monitoring the Comprehensive Nuclear-Test-Ban Treaty: Status, operations, and scientific application

Mon. May 27, 2024 3:30 PM - 4:45 PM 301A (International Conference Hall, Makuhari Messe)

convener:Dirk Metz(Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization), Akiko FURUNO(Japan Atomic Energy Agency), Hiroyuki Matsumoto(Japan Agency for Marine-Earth Science and Technology), Takayuki Otsu(Japan Weather Association), Chairperson:Dirk Metz(Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization), Hiroyuki Matsumoto(Japan Agency for Marine-Earth Science and Technology), Takayuki Otsu(Japan Weather Association), Akiko FURUNO(Japan Atomic Energy Agency)

4:00 PM - 4:15 PM

[HCG21-03] Discussion on the effects of applying the RSTT model as a velocity structure for hypocenter determination based on compariosn of event location in Japan

*Makiko Iwakuni1, Nobuo Arai1, Takayuki Otsu1, Masashi Motohashi1 (1.JAPAN WEATHER ASSOCIATION)

Keywords:the Regional Seismic Travel Time (RSTT)

CTBTO has a plan to deploy 50 Primary Seismic Stations (PS) and 120 Auxiliary Seismic Stations (AS) around the world, and approximately 90% of the seismic observation stations are currently in operation.

Using these seismic data, the epicenter is automatically determined by an CTBTO analysis system with a global velocity structure model. CTBTO's skilled analysts review these automatic hypocenter results and publish to many state signatories National Data Center (NDC) member as hypocenter catalogs (Reviewed Event Bulletin: REB). Determining the epicenter of a large earthquake using distant observation points can be done with relatively good accuracy, but the epicenter (event location and origin times) of regional earthquakes in subduction zones is somewhat low accuracy. The RSTT model is a local velocity structure model developed at Sandia National Laboratories, USA to accurately estimate the travel time of earthquakes within 1500 km. CTBTO has released REB whose epicenters were determined using the RSTT model since 2020.

Assuming the Japan Meteorological Agency (JMA)' s earthquake hypocenter in Japan as the ground truth, we present the results of how the accuracy of hypocenter determination changed after introducing the RSTT model.