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Travel time table, take-off angle table and seismic velocity structure files


Travel time table

JMA2020A travel time table (every 100 meters of sensor altitude):Used for OBS in Japan Trench landward slope areas
JMA2020B travel time table (every 100 meters of sensor altitude):Used for OBS in Japan Trench outer-rise areas
JMA2020C travel time table (every 100 meters of sensor altitude):Used for OBS in the Nankai Trough
JMA2001A travel time table (every 100 meters of sensor altitude):Used for land stations
Epicenter distance 0km – 2000km

Interval 0km – 50km 2km mesh


50km – 200km 5km mesh


200km – 2000km 10km mesh
Depth 0km – 700km

Interval 0km – 50km 2km mesh


50km – 200km 5km mesh


200km – 700km 10km mesh
JMA2001 travel time table
Epicenter distance 0km – 2000km

Interval 0km – 50km 2km mesh


50km – 200km 5km mesh


200km – 2000km 10km mesh
Depth 0km – 700km

Interval 0km – 50km 2km mesh


50km – 200km 5km mesh


200km – 700km 10km mesh
LL2001 travel time table (with LL adaptation to the JMA2001 mesh)
Epicenter distance 0km – 1490km

Interval 0km – 50km 2km mesh


50km – 200km 5km mesh


200km – 1490km 10km mesh
Depth 0km – 155km

Interval 0km – 50km 2km mesh


50km – 155km 5km mesh
83A travel time table
Epicenter distance 0km – 2000km

Interval
10km mesh
Depth 0km – 700km

Interval 0km – 200km 10km mesh


200km – 700km 20km mesh
LL travel time table
Epicenter distance 0km – 1490km

Interval
10km mesh
Depth 0km – 150km

Interval
10km mesh
Jeffreys & Bullen travel time table
Epicenter distance 2100km – 10000km

Interval
100km mesh
Depth 0km – 600km

Interval 0km – 200km 10km mesh


200km – 600km 20km mesh

Take-off angle table

Take-off angle table corresponding to JMA2020A
Take-off angle table corresponding to JMA2020B
Take-off angle table corresponding to JMA2020C
Take-off angle table corresponding to JMA2001, JMA2001A
Epicenter distance 0 – 2000km

Interval 0km – 50km 2km mesh


50km – 200km 5km mesh


200km – 2000km 10km mesh
Depth 0km – 700km

Interval 0km – 50km 2km mesh


50km – 200km 5km mesh


200km – 700km 10km mesh

However, for epicenter distances of 0 – 235 km and depths of 0 – 50 km, mesh intervals are all 1 km. (Updated in March 2023)

Take-off angle table corresponding to 83A
Epicenter distance 0km – 2000km

Interval 10km mesh
Depth 0km – 620km

Interval 0km – 200km 10km mesh


200km – 620km 20km mesh

However, for epicenter distances of 0 – 59 km and depths of 0 – 29 km, mesh intervals are all 1 km. (Updated in March 2023)

Take-off angle table for the far field
Epicenter distance 0 degree – 180 degrees

Interval 1 degree mesh
Depth 0km – 667km

Depth used for calculation 0km,33km,96km,160km,
223km,287km,350km,413km,
477km,540km,603km,667km

Seismic velocity structure

JMA2020A velocity structure file
JMA2020B velocity structure file
JMA2020C velocity structure file
JMA2001, JMA2001A velocity structure file
83A velocity structure file