ruaumoko: February 2010

Wednesday

2010 February 22nd Mt. Tihia Swarm

On February 22nd 2010 UTC a swarm of 24 earthquakes occurred on the south western flanks of Mt. Tihia. The swarm lasted 4 1/2 hrs between 05:01 and 9:33 UTC, with depths between 3km and 13km.
The deepest quake, the 1.988ML, was the most southern close to Lake Rotoaira.
No quakes were reported as felt.

REF, LAT, LONG, TIME, DEPTH, MAG
3265148, -38.99449, 175.68233, 2010/02/22 05:01:32.9, 5, 1.796
3265163, -39.00175, 175.69377, 2010/02/22 05:38:14.8, 5, 1.923
3265165, -38.99889, 175.70511, 2010/02/22 05:41:06.4, 5, 2.39
3265166, -38.99525, 175.69739, 2010/02/22 05:43:55.9, 5, 1.946
3265169, -38.9939, 175.69452, 2010/02/22 05:48:30.5, 8, 1.786
3265170, -38.99178, 175.70198, 2010/02/22 05:50:42.4, 5, 2.239
3265171, -38.99508, 175.70407, 2010/02/22 05:52:01.5, 6, 1.977
3265173, -38.99487, 175.70294, 2010/02/22 05:55:41.3, 3, 2.194
3265176, -39.01088, 175.71043, 2010/02/22 06:00:50.4, 13, 1.988
3265178, -38.99535, 175.70566, 2010/02/22 06:02:42.7, 5, 2.09
3265181, -38.99114, 175.67416, 2010/02/22 06:07:45.8, 4, 1.812
3265189, -38.99795, 175.6861, 2010/02/22 06:21:47.7, 6, 2.356
3265190, -38.99883, 175.68454, 2010/02/22 06:21:48.0, 5, 2.311
3265191, -38.99562, 175.67616, 2010/02/22 06:24:14.5, 5, 1.831
3265194, -38.99378, 175.69237, 2010/02/22 06:29:05.8, 6, 2.19
3265197, -38.99713, 175.6765, 2010/02/22 06:36:19.8, 3, 1.901
3265206, -39.00442, 175.69917, 2010/02/22 06:55:24.0, 5, 1.85
3265207, -39.00014, 175.69781, 2010/02/22 06:57:36.6, 5, 1.711
3265209, -39.00245, 175.69524, 2010/02/22 07:00:24.7, 6, 1.814
3265216, -39.00209, 175.69505, 2010/02/22 07:14:54.7, 6, 1.722
3265243, -38.99546, 175.68581, 2010/02/22 08:31:16.7, 5, 1.772
3265247, -38.99647, 175.68907, 2010/02/22 08:39:20.7, 5, 1.83
3265268, -38.99186, 175.68385, 2010/02/22 09:30:59.9, 7, 1.766
3265270, -38.99895, 175.68947, 2010/02/22 09:33:23.3, 6, 1.548

Mt. Tihia swarm February 22nd

data by geonet. map by google maps. plots by highace using GPS Visualizer

Saturday

2010 February 9th Swarm

On February 9th 2010 UTC a swarm of 31 earthquakes occurred between Tokaanu and Mt. Tihia. The majority of events (27) occurred between 10:47 and 12:12 UTC and three where reported as felt in the area, the 2.348ML, the 2.797ML and the 3.598ML.
REF, LAT, LONG, TIME, DEPTH, MAG
3254456, -38.9706, 175.7757, 2010/02/09 10:47:11.5, 6, 2.061
3254457, -38.9691, 175.7704, 2010/02/09 10:49:23.6, 5, 1.972
3254459, -38.9684, 175.7683, 2010/02/09 10:52:12.4, 5, 2.398
3254460, -38.9783, 175.7765, 2010/02/09 10:53:35.0, 5, 2.197
3254461, -38.9824, 175.7517, 2010/02/09 10:55:03.3, 6, 2.159
3254462, -38.9922, 175.7656, 2010/02/09 10:55:48.9, 4, 2.633
3254464, -38.9734, 175.7506, 2010/02/09 10:58:00.3, 1, 2.631
3254466, -38.9803, 175.7605, 2010/02/09 11:01:04.2, 8, 2.001
3254468, -38.9874, 175.742, 2010/02/09 11:03:26.3, 4, 2.797
3254470, -38.9601, 175.739, 2010/02/09 11:08:11.3, 4, 2.201
3254471, -38.9772, 175.7544, 2010/02/09 11:09:35.6, 5, 2.556
3254473, -38.9852, 175.7469, 2010/02/09 11:15:25.0, 4, 3.598
3254475, -38.9811, 175.8088, 2010/02/09 11:17:40.0, 0, 2.098
3254476, -38.9671, 175.7773, 2010/02/09 11:18:56.5, 4, 1.878
3254478, -38.9689, 175.7575, 2010/02/09 11:20:08.6, 4, 1.866
3254485, -38.9814, 175.7649, 2010/02/09 11:30:40.9, 8, 1.828
3254487, -38.9787, 175.7736, 2010/02/09 11:34:22.8, 7, 2.245
3254488, -38.9911, 175.7509, 2010/02/09 11:35:35.2, 5, 2.348
3254491, -38.9386, 175.8259, 2010/02/09 11:41:48.0, 5, 1.645
3254492, -38.9721, 175.7565, 2010/02/09 11:43:21.2, 5, 1.396
3254494, -38.9768, 175.7603, 2010/02/09 11:46:55.4, 7, 2.331
3254495, -39.002, 175.7105, 2010/02/09 11:46:56.0, 5, 2.006
3254498, -38.9715, 175.7225, 2010/02/09 11:53:44.3, 8, 1.564
3254499, -38.9824, 175.723, 2010/02/09 11:54:33.7, 5, 1.42
3254504, -38.9787, 175.7632, 2010/02/09 12:04:58.4, 7, 1.817
3254506, -38.9627, 175.7722, 2010/02/09 12:07:34.8, 5, 1.837
3254509, -38.9746, 175.7702, 2010/02/09 12:12:04.3, 7, 1.952
3254525, -38.9707, 175.7741, 2010/02/09 13:05:42.8, 7, 2.2
3254612, -38.9699, 175.7608, 2010/02/09 17:25:26.7, 7, 1.597
3254628, -38.9587, 175.7587, 2010/02/09 18:07:41.7, 5, 1.781
3254682, -38.9746, 175.7647, 2010/02/09 20:27:46.3, 7, 1.591

Mt. Tihia/Tokaanu swarm February 9th

data by geonet. map by google maps. plots by highace using GPS Visualizer

Earthquake Swarms

Earthquake swarms are events where a local area experiences sequences of many earthquakes striking in a relatively short period of time. The length of time used to define the swarm itself varies, but the United States Geological Survey points out that an event may be on the order of days, weeks, or months. They are differentiated from earthquakes succeeded by a series of aftershocks by the observation that no single earthquake in the sequence is obviously the main shock. Earthquake swarms are one of the events typically preceding eruptions of volcanoes

Earthquake Aftershocks

An aftershock is an earthquake that occurs after a previous earthquake (the main shock). An aftershock is in the same region of the main shock but is always of smaller magnitude strength. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock. Aftershocks are smaller earthquakes formed as the crust around the displaced fault plane adjusts to the effects of the main shock

Aftershocks are dangerous because they are usually unpredictable, can be of a large magnitude, and can collapse buildings that are damaged from the mainshock. Bigger earthquakes have more and larger aftershocks and the sequences can last for years or even longer especially when a large event occurs in a seismically quiet area; see, for example, the New Madrid Seismic Zone, where events still follow Omori's law from the mainshocks of 1811–1812. An aftershock sequence is deemed to have ended when the rate of seismicity drops back to a background level; i.e., no further decay in the number of events with time can be detected.