Magnitude 7.8 M Earthquake Strikes Off West Coast of South Island, New Zealand
A powerful earthquake measuring magnitude 7.8 occurred off west coast of South Island, New Zealand, about 150 km WNW of Invercargill, at 09:22:32 UTC, USGS reported.
The mainshock, which occurred at a depth of 35 km, was followed by a large aftershock measuring 5.8 Mw some 20 km WSW of the mainshock about 20 minutes later. [Location, 45.991°S, 166.238°E; depth, 35km; event ID, us2009jcat/USGS]
The aftershock was reported as measuring 6.1 on Richter scale, and at a depth of 5km, by New Zealand’s GNS Science Earthquake Information.
FEWW EarthModel simulations suggest the latest earthquakes may well be a prelude to an extended period of intense, likely catastrophic, seismic and volcanic activities in the New Zealand region. Lots of ‘fireworks’ may follow. [See links below for forecasts and travel advisories.]
On May 9, 2009, FEWW Moderators issued the following warning to tourists planning to visit New Zealand:
A Warning to Visitors to New Zealand:
Climatological and Geological Warning! The New Zealand region is about to experience significant climatological events and large-scale geological and tectonic activity over an extensive period of time. Would be visitors are advised to stay out of the area for the foreseeable future. http://newzeelend.wordpress.com/2009/05/09/a-warning-to-new-zealand-visitors/
New Zealand’s Alpine Fault – Source: Stuff NZ. Image may be subject to copyright. SEE Fair Use Notice!
What the local experts said
It’s interesting and quite comforting [sic] to note, as our colleague TERRES pointed out earlier, the local experts had assured New Zealanders “there was no cause for worry,” and that the frequent quakes earlier this year were not “leading up to the ‘big one.'” http://www.stuff.co.nz/national/2308107/Quakes-no-cause-for-worry
10-degree Map Centered at 45°S,165°E
Earthquake Location. Original Map: USGS – EHP
Earthquake Details:
- Magnitude: 7.8
- Date-Time:
- Wednesday, July 15, 2009 at 09:22:32 UTC
- Wednesday, July 15, 2009 at 08:22:32 PM at epicenter
- Location: 45.721°S, 166.643°E
- Depth: 35 km (21.7 miles) set by location program
- Region: OFF WEST COAST OF THE SOUTH ISLAND, N.Z.
- Distances:
- 150 km (95 miles) WNW of Invercargill, New Zealand
- 175 km (110 miles) WSW of Queenstown, New Zealand
- 300 km (185 miles) W of Dunedin, New Zealand
- 825 km (510 miles) SW of WELLINGTON, New Zealand
- Location Uncertainty: horizontal +/- 11.1 km (6.9 miles); depth fixed by location program
- Parameters: NST= 44, Nph= 44, Dmin=322.8 km, Rmss=1.58 sec, Gp= 54°, M-type=teleseismic moment magnitude (Mw), Version=7
- Source: USGS NEIC (WDCS-D)
- Event ID: us2009jcap
Seismic Hazard Map [USGS]
Major Tectonic Boundaries: Subduction Zones -purple, Ridges -red and Transform Faults -green
Population exposure estimates are NOT a direct estimate of earthquake damage; comparable shaking will result in significantly lower losses in regions with well built structures than in regions with vulnerable structures. [USGS]
Notes:
On September 30, 2008, FEWW wrote:
Magnitude 7 Earthquake Hits Kermadec Islands
Implication for New Zealand Islands:
- A substantial increase in the frequency of earthquake striking the twin islands.
- More earthquakes with magnitude 6 or larger.
- A marked increased in large explosive volcanic eruptions, especially in the following zones [also includes ‘extinct’ volcanoes]
- Taupo Volcanic Zone
- Bombay Hills
- Auckland volcanic field
- Mount Taranaki
- Mt Horrible volcano
- Mount Taranaki
- Mount Cargill
Worst Case Condition for New Zealand Islands:
Will a magnitude 9.8 (MW) earthquake centered at 42° 00′ 59″ South, 175° 05′ 07″ East herald the end of New Zealand Islands?
- Large earthquakes and massive volcanic eruptions could potentially destroy much of New Zealand structures and claim many lives.
- Earthquake and volcano-triggered waves could also give rise to 40 to 50-meter tsunami that would engulf the coastal areas and low-lying lands throughout New Zealand [could also affect parts of Australia’s eastern seaboard,] compounding the damage.
- A super/mega colossal Plinian/Ultra-Plinian eruption occurring in New Zealand’s North Island simultaneously [or within a short period of time] with a magnitude 9.8 earthquake off the eastern coast of New Zealand could claim many lives.
- Probability of occurrence:
- Event 1. A magnitude 9.8 earthquake striking off the eastern coast of New Zealand with (i) the foreshocks ripping through Auckland, Hamilton, Taupo areas, (ii) the mainshock leveling Wellington, Palmerstone North, Marlborough, Nelson and Christchurch, and (iii) the aftershock causing substantial damage as far south as Invercargill: 85%
- Event 2. A super/ mega colossal Plinian/Ultra-Plinian eruption in the North Island: 72% [South Island: 57%]
- Event 1 and Event 2 occurring simultaneously, or within a short period of time: 64 %
Related News Links:
Related Links:
Fire Earth 