Residents of northern Westland may have felt slightly more local earthquakes than normal during March. The five earthquakes occurred near Westport, Reefton and Murchison.
Archive for March, 2007
Two 5th magnitude earthquakes have struck the Kermadec Islands in recent days.
The first was a magnitude 5.2 quake which struck at 7:21 a.m. on March 26th 2007, NZ Standard Time. It was located 180 km NNE of Raoul Island at a depth of 51 km.
The second event struck last night at 8:08 p.m. on the 28th March 2007. This was a magnitude 5.7 quake located 170 km south of Raoul Island at a depth of 35 km.
Another dry spell in Tawa seems set to be broken by anticipated showers later today. The latest run of 9 days without rain confirms the welcome effect of an “Indian summer” which has allowed us to enjoy a late end to a summer that seemed reluctant to start.
Sunday’s earthquakes near Vanuatu were a mainshock pair instead of a mainshock-aftershock pair. Following further analysis, the U.S. Geological Survey (USGS) has revised its magnitude estimates and location data for the events.
The revision brings the USGS data more in line with data supplied by Geoscience Australia.
The swarm of earthquakes occurring within 10 km of the Bay of Plenty township of Matata has continued throughout March.
Today’s major earthquake and strong aftershock near Vanuatu follow a week of increased earthquake activity in that part of the South Pacific. Seven earthquakes of magnitude 4.3 or greater have struck the area since March 18th.
A major earthquake struck near Vanuatu at 12:40 NZST today, Sunday 25th March 2007. The magnitude 7.2 earthquake was located 115 km south of Isangel, Tanna, Vanuatu at a depth of 35 km according to provisional information supplied by the U.S. Geological Survey.
It was followed two minutes later by a 32 km deep magnitude 6.7 earthquake 105 km north of Kanazawa, Honshu, Japan.
The Pacific Tsunami Warning Centre issued bulletins on both events, but the transition to the U.S. National Oceanic and Atmosphere Administration (NOAA) website appears to have caused problems with accessing some data. Of the two, only the bulletin concerning the event near Japan is available, and this suggests that a Pacific-wide tsunami threat does not exist.
Whilst the PTWC bulletin concerning the Vanuatu quake is not currently accessible, the site’s map indicates that the bulletin considered the tsunami threat as low.
Selected members of the Galactic Senate meet at frequent, but irregular, intervals to discuss matters of glactic import.
At the latest meeting, the emperor Derolan Calna Voroseii Anacreon III met with his senior administrators to consider the threat presented by the Pengoon invasion, a new but secretly-named race of galactic invaders, the Matata earthquake swarm, Sir Patrick Moore’s latest television programme, Seifried’s newest offering, and other weighty matters.
The venue was the Thai Country Cafe on the corner of Main Road and Oxford Street in Tawa.
The levels of New Zealand’s hydro-electric storage lakes declined further during February 2007, continuing the trend set in December 2006. By month’s end, storage was 94% of the average for the time of year, having slid to below average levels on the 21st.
Volcanic earthquake activity at Mt. Ruapehu has increased since Sunday’s lahar, indicating that there may be a consequent increase in activity within the crater lake over the next few days to weeks.
Yesterday’s lahar on Mt Ruapehu has been described as bigger than the lahar that followed Ruapehu’s 1995 eruption but smaller than the destructive Tangiwai lahar of 1953 that claimed 151 lives.
Summary: 5.3 metre lahar recorded at Tangiwai flood gauge. Bund protecting spill into Waikato Stream intact. Road and rail traffic suspended in the area. Minor damage. Tephra dam not completely destroyed. Management plan successful.
The forecast lahar from Mt Ruapehu’s crater lake flowed down the mountainside late this morning.
Since the 1995 and 1996 eruptions, the crater lake on the volcano has risen behind a weak tephra dam which accumulated to a depth of 6-7 metres on the usual outlet on the south-eastern rim of the crater.
Earthquake swarm activity occurring near Matata has increased during March.
Earthquake activity continued at a low level. White Island, Mt Ngauruhoe, and Mt Ruapehu remained at Alert Level 1.
Geonet, the USGS (NEIC) and IGNS reported 38 earthquakes in the New Zealand area between the Kermadec Islands in the north, and the Auckland Islands to the south during February 2007. The magnitude distributions were as follows:
M6 to 6.9 (none), M5 to 5.9 (4), M4 to 4.9 (9) M3 to 3.9 (16).
An additional 9 events in the magnitude 2 range were deemed worthy of mention.