* Focal Mechanism Solution derived from NIED F-net and NIED Hi-net


This map shows the focal mechanisms of the main and aftershocks.
The CMT solutions determined by the NIED F-net are indicated by dark blue (for the mainshock) and light blue (for aftershocks) and the first motion solutions derived from the NIED Hi-net waveforms are shown by red (the mainshock) and orange (aftershocks). Red dots denote the distribution of aftershocks determined by the Hi-net. Blue lines and white squares are active faults and the location of the Hi-net stations, respectively.
So far, almost all events with magnitude greater than 5.5 have reverse-fault type solutions and their P-axes are oriented in NW-SE. Strikes of fault planes are about NE-SW. This direction is consistent with the distribution of aftershocks and the strike of active faults around the source region.

* F-net CMT Solutions in and around Niigata Pref.(Jan. 01,1997 - Oct. 23, 2004)
* F-net CMT Solutions in and around Niigata Pref.(Oct. 23,2004 - Nov. 08, 2004)
* F-net CMT Solutions in and around Niigata Pref.(Oct. 23,2004 - Nov. 08, 2004) - With Geographic Information -
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Mechanism
ID Hi-net Hypocenter Information F-net CMT Solution Information
Origine Time (JST) Lat.(N) Lon.(E) Depth Mag. Strike Dip Slip Depth Mw Strike Dip Slip V.R.
1 10/23 17:56:00 37.28 138.88 13.4 6.5 208/ 16 49/41 98/ 81 5.0 6.5 211/ 27 52/38 93/ 87 86.88
2 10/23 18:03:13 37.35 139.00 7.2 5.8 242/ 19 37/61 126/ 66 5.0 6.0 216/ 17 48/44 103/ 76 88.78
3 10/23 18:11:57 37.24 138.84 14.1 5.9 270/ 6 63/78 167/ 28 8.0 5.7 16/226 56/38 72/115 88.79
4 10/23 18:34:06 37.30 138.94 11.3 6.4 38/203 26/65 104/ 83 11.0 6.2 221/ 39 58/32 91/ 88 89.04
5 10/23 19:45:57 37.28 138.89 15.6 5.6 246/ 16 45/58 130/ 58 8.0 5.5 20/215 50/41 80/101 82.12
6 10/25 06:04:58 37.32 138.96 11.7 5.6 246/337 88/72 162/ 2 14.0 5.6 212/ 31 50/40 91/ 89 85.78
7 10/27 10:40:50 37.29 139.04 11.3 6.1 40/180 54/44 117/ 59 11.0 5.9 216/ 24 57/34 96/ 81 90.01
8 11/08 11:15:59 37.39 139.03 6.8 5.5 18/180 49/42 102/ 77 5.0 5.5 13/209 53/38 80/103 93.38
* These information may be updated.
* F-net CMT Solutions in and around Niigata Pref.(Jan. 01,1997 - Oct. 23, 2004)
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F-net CMT Solutions Enlargement
* Enlargement
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Enlargement
* F-net CMT Solutions in and around Niigata Pref. (Oct. 23,2004 - Nov. 08, 2004)
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F-net CMT Solutions
* F-net CMT Solutions in and around Niigata Pref. (Oct. 23,2004 - Nov. 08, 2004) - With Geographic Information -
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F-net CMT Solutions - With Geographic Information -