Geonet Analyse yesterday’s Earthquakes

Geonet were prompt to analyse the reports submitted by members of the public who felt yesterday’s earthquakes, posting an updated report at 6 a.m. today. The report is available via the Earthquake Information link on this blogsite, and is accessed by clicking on “News” at the top of the Geonet webpage.

The magnitude 5.0 northern Wairarapa earthquake at 2:55 a.m. which knocked items off shelves in Dannevirke attracted 294 “felt reports” from the public.

The magnitude 4.5 earthquake near Porirua at 9:09 p.m. which knocked items from shelves in Porirua, Wellington and the Hutt Valley attracted 532 “felt reports” from the public. The worst damage was reported from Titahi Bay.

So many people responded to the second earthquake, that Geonet apologised for problems that were encountered in filing reports on their server. Seismologists use the data from “felt reports” to refine their seismic hazard modelling tools, and the large response from the public is to be applauded.

The “felt earthquake” programme was started by the Seismological Observatory in the days of the Department of Scientific and Industrial Research. Back then, pre-paid report forms were completed and mailed to the observatory. Details about the quake were mailed back to respondents to acknowledge their contribution. With the launch of the Geonet website, it soon became possible to file a report on-line. However, the code that was written made it difficult for linux and Mozilla users to file reports. It is hoped that any revamp of the site will take the opportunity to write code that can be used by browsers other than Microsoft’s Internet Explorer.

The National Earthquake Information Centre, which is operated by the United States Geological Survey was forced to revamp its website after last year’s Boxing Day earthquakes and tsunami. The entry page contained a handy interactive world map of latest earthquakes but the demand was so high, that the servers groaned under the load caused by international interest in the events. The site now greets users with a list of earthquake events, with the CPU-intensive interactive maps being nested on deeper pages.

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