As observed five days ago, Alpine and/or Wellington fault movement seems on its way, if not already haltingly started. Aotearoa-Zealandia is triangulated amidst an ever-increasing series of southern hemisphere and south Pacific earthquakes, adding evermore energy into our already lively local tectonic system:

Monday July 18 2011, 22:38:39 UTC Rat Islands, Aleutian Islands, Alaska 5.9 18.7
Monday July 18 2011, 16:03:50 UTC Kermadec Islands region 5.2 47.4 [2]
Monday July 18 2011, 15:55:51 UTC Vanuatu 4.7 37.3
Monday July 18 2011, 03:20:27 UTC Vanuatu 4.7 208.9
Monday July 18 2011, 02:35:40 UTC Fiji region 4.6 532.4
Monday July 18 2011, 00:43:02 UTC Negros, Philippines 4.9 41.3
Sunday July 17 2011, 17:34:43 UTC New Britain region, Papua New Guinea 4.7 35.0
Sunday July 17 2011, 11:39:47 UTC south of the Kermadec Islands 5.2 46.2 (off NZ)
Sunday July 17 2011, 09:55:52 UTC off the coast of Central America 4.4 10.0
Sunday July 17 2011, 07:08:06 UTC Kermadec Islands, New Zealand 4.8 35.3
Saturday July 16 2011, 21:54:07 UTC Kermadec Islands region 5.0 20.1
Saturday July 16 2011, 19:59:13 UTC Alaska Peninsula 6.1 40.0
Saturday July 16 2011, 18:09:41 UTC Vanuatu 5.5 247.0
Saturday July 16 2011, 17:06:39 UTC Kepulauan Barat Daya, Indonesia 5.8 246.2
Saturday July 16 2011, 07:03:37 UTC Tonga region 5.9 35.7
Saturday July 16 2011, 00:26:13 UTC offshore Valparaiso, Chile 6.0 22.9
Friday July 15 2011, 21:45:07 UTC Kermadec Islands region 5.1 50.0
Friday July 15 2011, 16:14:16 UTC Kermadec Islands region 5.1 37.7

Friday July 15 2011, 15:00:51 UTC Vanuatu 5.4 57.1
Friday July 15 2011, 14:55:30 UTC Potosi, Bolivia 5.3 87.3
Friday July 15 2011, 13:26:02 UTC South Sandwich Islands region 5.9 9.9
Friday July 15 2011, 12:01:09 UTC near the east coast of Honshu, Japan 5.3 60.2
Friday July 15 2011, 08:42:09 UTC Kermadec Islands region 5.0 34.4
Friday July 15 2011, 07:41:24 UTC Fiji region 4.8 609.1
Friday July 15 2011, 05:50:28 UTC Kermadec Islands region 5.1 43.8 [1]
Friday July 15 2011, 05:27:44 UTC south of the Fiji Islands 4.7 510.2
Friday July 15 2011, 00:55:47 UTC south of Tonga 5.6 43.2
Thursday July 14 2011, 22:53:55 UTC southern Peru 4.5 240.9
Thursday July 14 2011, 21:47:46 UTC Fox Islands, Aleutian Islands, Alaska 4.5 48.0
Thursday July 14 2011, 18:57:36 UTC Tarapaca, Chile 4.9 108.0
Thursday July 14 2011, 11:17:32 UTC West Chile Rise 5.2 9.8
Thursday July 14 2011, 09:12:23 UTC near the coast of Nicaragua 4.3 35.9
Thursday July 14 2011, 08:52:32 UTC West Chile Rise 5.4 10.5
Thursday July 14 2011, 08:49:24 UTC West Chile Rise 5.3 10.5
Thursday July 14 2011, 05:51:32 UTC Western Australia 4.5 10.1
(fuller list in Kermadec collision continued)

Kermadec magnitude 5.2 quake - GIM 180711

Kermadec magnitude 5.2 quake - GIM 180711


magnitude 5.2 quake off North Island NZ - GIM 170711b

magnitude 5.2 quake off North Island NZ - GIM 170711b


Tonga magnitude 5.9 quake - USGS 160711

Tonga region magnitude 5.9 quake - USGS 160711


South Sandwich Island magnitude 5.9 quake - GIM 160711

South Sandwich Island magnitude 5.9 quake - GIM 160711

And then there is the biggest recent 4+ Canterbury aftershock,
Magnitude 4.4, Saturday, July 16 2011 at 11:11 am (NZST), 10 km east of Christchurch. Anything unusual about that?:

Sumner magnitude 4.4 quake - GNS GoogleMap 160711

Sumner magnitude 4.4 quake - GNS GoogleMap 160711


Why yes, as it happens:
Canterbury seismograph drums - GNS 160711

Canterbury seismograph drums - GNS 160711


[1] Note the remote record here of a Kermadec Trench 5.1 quake, that appears on all Canterbury seismographs in top-left quadrant – except for Inchbonnie. A clear difference in forces and effects on different sides and parts of the Alpine fault is thus discernable.

But the real eye-opener here is how two smaller quakes sourced on the same latitude as the ancient Chatham Rise orogeny, but on the west side of the Southern Alps – in the Waitaha Valley – soon triggered this 4.4 ‘aftershock’ under Banks Peninsula on the east side of the Alps:

Waitaha Valley seismograph drum, Sumner mag 4.4 - GNS 160711

Waitaha Valley seismograph drum, Sumner mag 4.4 - GNS 160711

[2] The July 18 magnitude 5.2 south of the Kermadec Islands / off NZ, in bottom left quadrant of each Canterbury seismograph here, but again not recorded in Inchbonnie (yet..):

Canterbury seismograph drums - GNS 170711b

Canterbury seismograph drums - GNS 170711b

Ask an Expert: Alpine Fault fears The Press 06/07/2011

Ruapehu volcano seismograph - GNS 190711

Ruapehu volcano seismograph - GNS 190711

21 July 2011 update
Alpine fault indicators, as followed above, are being read correctly:
Magnitude 4.7, Thursday, July 21 2011 at 8:38 am (NZST), 80 km west of Te Anau
See Waitaha kicks back next blogpost.

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