Mauna Kea, Hawaii – earthquake swarm below the astronomical observatories volcano

Last update: October 20, 2011 at 1:56 pm by By

The dry summit environment of the summit of Mauna Kea - The white points on the summit are the astronomical telescopes - Image courtesy Tony Romaine

Description: At 00:10 AM UTC October 20, a moderate earthquake with a magnitude of 4.5 and a depth of 18.8 km attracted our attention. To our surprise the epicenter was located below the slopes of Mauna Kea, an active shield volcano who’s last eruption occurred at approx. 2,400 BC.

Update 13:37 UTC :  The present earthquake swarm is  not necessarily to be linked to volcanic activity since occasional swarms have been registered since 25 years. The swarms are linked to structural adjustments within the Earth’s crust due to the heavy load of Mauna Kea.
A similar earthquake swarm occurred in March 2010. The aftershocks (just like they are occurring now) continued for many days in a row.

Update 12:28 UTC :  Mauna Kea shield volcano is presently called “dormant”.

Update 11:13 UTC : USGS maintains her NORMAL green color alert (no problem)

Update 10:23 UTC : Since the mainshock at 00:10 earlier today, we noticed 38 other earthquakes. The shallowest of the +1 magnitude earthquakes was at a depth of 14.3 km.

The shallower earthquakes at Fern forest and Volcano have to be linked to the Kilauea complex.
21 km (13 miles) SE (137°) from Waimea, HI and 23 km (14 miles) SSW (199°) from Honokaa, HI

Earthquake swarm below Mauna Kea on October 20 2011

Magn    Date              Time   Depth   Distance from reference point
2.2     2011/10/20 10:50  13.9      22 km ( 14 mi) SE of Waimea, HI
2.5     2011/10/20 10:05  17.8      21 km ( 13 mi) SE of Waimea, HI
2.1     2011/10/20 09:55  17.2      21 km ( 13 mi) SE of Waimea, HI
3.4     2011/10/20 09:42  15.3      23 km ( 14 mi) SE of Waimea, HI
2.8     2011/10/20 09:32  16.4      21 km ( 13 mi) SE of Waimea, HI
2.4     2011/10/20 08:08  17.3      22 km ( 13 mi) SE of Waimea, HI
2.2     2011/10/20 06:39  18.1      21 km ( 13 mi) SE of Waimea, HI
2.1     2011/10/20 06:15  17.4      21 km ( 13 mi) SE of Waimea, HI
2.6     2011/10/20 06:04  16.6      20 km ( 13 mi) SE of Waimea, HI
2.4     2011/10/20 04:42  17.7      21 km ( 13 mi) SE of Waimea, HI
1.9     2011/10/20 04:32  19.2      21 km ( 13 mi) SE of Waimea, HI
2.2     2011/10/20 04:12  16.6      22 km ( 13 mi) SE of Waimea, HI
2.5     2011/10/20 03:21  14.3      21 km ( 13 mi) SE of Waimea, HI
2.7     2011/10/20 03:16  19.3      21 km ( 13 mi) SE of Waimea, HI
2.3     2011/10/20 02:14  14.8      24 km ( 15 mi) SE of Waimea, HI
2.0     2011/10/20 01:48  17.6      21 km ( 13 mi) SE of Waimea, HI
2.2     2011/10/20 01:42  17.2      19 km ( 12 mi) SE of Waimea, HI
2.3     2011/10/20 01:29  17.0      21 km ( 13 mi) SE of Waimea, HI
2.5     2011/10/20 01:24  17.9      22 km ( 13 mi) SE of Waimea, HI
2.1     2011/10/20 01:22  17.6      20 km ( 12 mi) SE of Waimea, HI
2.7     2011/10/20 01:11  17.0      23 km ( 14 mi) SE of Waimea, HI
2.1     2011/10/20 01:04  18.0      21 km ( 13 mi) SE of Waimea, HI
3.3     2011/10/20 00:59  19.5      21 km ( 13 mi) SE of Waimea, HI
2.4     2011/10/20 00:57  14.8      23 km ( 14 mi) SE of Waimea, HI
2.6     2011/10/20 00:48  16.7      21 km ( 13 mi) SE of Waimea, HI
2.4     2011/10/20 00:45  14.7      24 km ( 15 mi) SE of Waimea, HI
2.8     2011/10/20 00:45  15.2      21 km ( 13 mi) SE of Waimea, HI
2.1     2011/10/20 00:33  18.1      20 km ( 12 mi) SE of Waimea, HI
1.7     2011/10/20 00:31  16.2      24 km ( 15 mi) SE of Waimea, HI
2.5     2011/10/20 00:27  18.6      21 km ( 13 mi) SE of Waimea, HI
2.4     2011/10/20 00:25  16.3      21 km ( 13 mi) SE of Waimea, HI
3.1     2011/10/20 00:21  15.7      22 km ( 13 mi) SE of Waimea, HI
2.0     2011/10/20 00:18  16.9      24 km ( 15 mi) SE of Waimea, HI
1.9     2011/10/20 00:16  17.8      21 km ( 13 mi) SE of Waimea, HI
1.9     2011/10/20 00:13  15.8      23 km ( 14 mi) SE of Waimea, HI
3.6     2011/10/20 00:12  18.4      22 km ( 14 mi) SE of Waimea, HI
4.5     2011/10/20 00:10  18.8      21 km ( 13 mi) SE of Waimea, HI

Volcano information
Mauna Kea, Hawaii’s highest volcano, reaches 4205 m, only 35 m above its neighbor, Mauna Loa. In contrast to Mauna Loa, Mauna Kea lacks a summit caldera and is capped by a profusion of cinder cones and pyroclastic deposits. Mauna Kea’s rift zones are less pronounced than on neighboring volcanoes, and the eruption of voluminous, late-stage pyroclastic material has buried much of the early basaltic shield volcano, giving the volcano a steeper and more irregular profile. This transition took place about 250,000 to 200,000 years ago, and much of Mauna Kea, whose Hawaiian name means “White Mountain,” was constructed during the Pleistocene. Its age and high altitude make it the only Hawaiian volcano with glacial moraines. A road that reaches a cluster of astronomical observatories on the summit also provides access to seasonal tropical skiing. The latest eruptions at Mauna Kea produced a series of cinder cones and lava flows from vents on the northern and southern flanks during the early to mid Holocene. (info courtesy Smithsonian Institute).

Wikipedia information on Mauna Kea

Mauna Kea is a volcano on the island of Hawaii. Standing 4,205 m (13,796 ft) above sea level, its peak is the highest point in the state of Hawaii. However, much of the mountain is under water; when measured from its oceanic base, Mauna Kea is over 10,000 m (33,000 ft) tall—significantly taller than Mount Everest. Mauna Kea is about a million years old, and has thus passed the most active shield stage of life hundreds of thousands of years ago. In its current post-shield state, its lava is more viscous, resulting in a steeper profile. Late volcanism has also given it a much rougher appearance than its neighboring volcanoes; contributing factors include the construction of cinder cones, the decentralization of its rift zones, the glaciation on its peak, and the weathering effects of the prevailing trade winds.

In Hawaiian mythology, the peaks of the island of Hawaii are sacred, and Mauna Kea is the most sacred of all. An ancient law allowed only high-ranking tribal chiefs to visit its peak. Ancient Hawaiians living on the slopes of Mauna Kea relied on its extensive forests for food, and quarried the dense volcano-glacial basalts on its flanks for tool production. When Europeans arrived in the late 18th century, settlers introduced cattle, sheep and game animals, many of which became feral and began to damage the mountain’s ecology.

With its high altitude, dry environment, and stable airflow, Mauna Kea’s summit is one of the best sites in the world for astronomical observation, and one of the most controversial. Since the creation of an access road in 1964, thirteen telescopes funded by eleven countries have been constructed at the summit. The Mauna Kea Observatories are used for scientific research across the electromagnetic spectrum from visible light to radio, and comprise the largest such facility in the world. Their construction on a “sacred landscape”, replete with endangered species, ongoing cultural practices, and viewplanes used in the traditional Hawaiian measurement of time, continues to be a topic of intense debate and protest.

Initial Earthquake information

M 4.5      2011/10/20    00:10     Depth 18.8 km     ISLAND OF HAWAII, HAWAII
02:10:04 PM at epicenter
Epicenter deep below Mauna Kea. Mainshock followed by many aftershocks.
Mauna Kea is an active shield volcano who had his last eruption approx. 2400 BC (error margin 100 years). The top of Mauna Kea has a lot of star gazing telescopes.
Update 10:23 UTC : Since the mainshock at 00:10 earlier today, we noticed 38 other earthquakes. The shallowest of the +1 magnitude earthquakes was at a depth of 14.3 km.
The shallower earthquakes at Fern forest and Volcano have to be linked to the Kilauea complex.
21 km (13 miles) SE (137°) from Waimea, HI and 23 km (14 miles) SSW (199°) from Honokaa, HI
Satellite map of the greater epicenter area

 

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