article: Dec 17 2004 - Puysegur Trench Event Generates Hundreds of Felt Reports

To date, 833 felt earthquake reports have been received by the GeoNet Data Centre for the Puysegur Trench event.

The accompanying map shows the distribution of places where the public have reported the effects of the November 23 magnitude 7.3 event. The colours represent the most commonly reported experiences at a locality. All reports have now been analysed and reviewed where necessary.

The Modified Mercalli (MM) shaking levels, the brief definition of their effects on people, and the localities that experienced them, are shown below. Where a number appears in square brackets [n], 'n' reports were received from that locality:

• MM 7 - "General alarm. Difficulty experienced in standing. Noticed by motorcar drivers who may stop":
  Cromwell.
  
  
• MM 6 - "Felt by all. People and animals alarmed. Many run outside. Difficulty experienced in walking steadily":
  Balclutha, Cromwell [3], Dunedin [2], Gore, Halfmoon Bay (Oban), Invercargill [17], Kingston, Lawrence, Mataura [2], Milton, Orawia, Queenstown [2], Riverton/Aparima [3], Scotts Gap, South Dunedin, Te Anau [2], Waikiwi, Waikouaiti [2], Wanaka.
  
  
• MM 5 - "Generally felt outside, and by almost everyone indoors. A few people alarmed":
  Alexandra [2], Andersons Bay, Appleby, Christchurch [2], Conical Hill, Dunedin [14], East Gore, Frankton, Gore, Greymouth, Grove Bush, Halfway Bush, Invercargill [34], Isla Bank, Kaiapoi, Kaitangata [2], Kingston [2], Kingswell, Lumsden, Maori Hill, Milford Sound, Milton, Mosgiel [2], Newfield, North Dunedin [2], North East Valley, Oamaru, Ohai, Otatara [2], Owaka, Owaka Valley, Queenstown [6], Remarkables Station, Riverton/Aparima, Rosedale, Sockburn, South Dunedin [3], Te Anau [6], Te Anau Downs, Wanaka [4], Waverley, Wyndham.
  
  
• MM 4 - "Generally noticed indoors but not outside. Vibration may be likened to the passing of heavy traffic, or to the jolt of a heavy object falling or striking the building":
  Abbotsford [4], Addington [2], Alexandra [12], Andersons Bay, Aoraki/Mount Cook, Ashburton [4], Avenal, Balclutha [2], Balfour, Belfast, Bell Block, Bluff [2], Burnside, Casebrook, Caversham, Cecil Peak, Charlton, Christchurch [62], Clifton, Cobden, Corstorphine, Cromwell [6], Dallington, Dipton, Doubtful Sound/Patea, Dunedin [61], East Gore, Edendale [2], Fernhill, Ferrymead, Frankton [3], Franz Josef, Glengarry, Glenleith, Glenorchy, Gore [8], Grasmere, Green Island [2], Greymouth [3], Haast, Halswell, Hamilton, Harewood, Harihari, Hawera, Hawthorndale, Hector, Heddon Bush, Hokitika [5], Hornby, Ilam [6], Inch Clutha, Invercargill [55], Kaiteriteri, Karamea [3], Kelvin Heights, Kennington, Kew, Kingswell, Lake Coleridge [2], Lake Paringa, Lincoln [2], Little River, Lorneville [2], Lower Hutt, Luggate [2], Lumsden [2], Mairehau, Manapouri, Maori Hill [2], Mataura, Merivale, Moeraki, Mornington, Mosgiel [7], Mount Aspiring, Musselburgh [2], Nelson [4], Nelson South [2], New Plymouth [2], Newfield [3], Ngapara, North Dunedin [16], North East Valley, North New Brighton, Oamaru [4], Omarama, Opoho, Orewa, Otatara, Otautau [2], Otematata, Owaka, Papanui [4], Pukerau, Purakaunui, Queenstown [18], Raumati South, Riccarton [3], Riverton/Aparima [5], Roslyn, Roxburgh [2], Runanga [2], Saint Albans, Saint Bathans, Saint Kilda [2], Somerfield, South Dunedin [12], Spencerville, Springvale, Sydenham, Tainui, Takaka, Tapanui [2], Te Anau [10], Te Anau Downs, Te Tipua, Temuka, Teviot, Timaru [7], Tokanui [2], Tuatapere [3], Twizel, Upper Riccarton, Waihao Downs, Waikaia, Waikiwi, Waikouaiti, Waitangi, Chatham Islands, Wallacetown, Wanaka [8], Wellington [21], West Plains, Westport [6], Whiterigg, Windsor, Winton [6], Woolston.
  
  
• MM 3 - "Felt indoors; hanging objects may swing, vibration similar to passing of light trucks, may not be recognised as an earthquake":
  Auckland, Broad Bay, Christchurch [30], Cromwell, Dunedin [7], Frankleigh Park, Green Island, Halfway Bush, Hamilton [3], Hawera, Hokitika [2], Hornby, Ilam [3], Kelburn, Kew, Linwood, Lower Hutt [3], Middleton, Mornington, Mosgiel, Mossburn, Motueka, Moturoa, Nelson [3], New Plymouth [6], Newmarket, North Dunedin [4], Omata, Opawa, Palmerston, Palmerston North [2], Papanui [2], Papatotara, Petone, Porirua, Port Chalmers, Queenstown [3], Redcliffs, Riccarton [6], Richmond, Shiel Hill, South Dunedin, Spotswood, Tahunanui, Timaru, Twizel [2], Upper Waitati, Waimate, Wairakei Village, Wanganui, Wanganui East, Wellington [63], Westown, Westport [2], Woolston.
  
  
• MM 2 - "Felt by persons at rest, on upper floors or favourably placed":
  Nelson.
  

We are working towards improving our felt earthquake questionnaire and allowing the information shown above to be generated automatically for all earthquakes felt in New Zealand. We thank all those who took the time and trouble to contribute with their own experiences.

We apologise to those who found the web site slow or unresponsive in the first hour after the event; we have reviewed the performance of our web servers and are confident of delivering a better service next time.