A series of earthquakes have struck the Christchurch region of New Zealand’s South Island on Monday, June 13. A 5.2 (body wave) magnitude struck and was soon followed by a stronger 6.0 (moment) magnitude earthquake. A further earthquake, of 4.6 (body wave) magnitude, struck at 02:40 pm local time. (As reported by the USGS).
According to both the New Zealand GeoNet network and USGS the 6.0 magnitude earthquake, which struck at 02:20 pm local time, occurred at a depth of 5.6 miles and at an epicentral location around 8 miles south-southeast of Christchurch and within 3 miles of the port of Lyttelton. Information from the USGS ShakeMap and USGS PAGER system show that the area close to the epicenter, which includes the city of Christchurch, experienced ‘severe’ shaking of intensity VIII on the Modified Mercalli Intensity (MMI) scale. The New Zealand GeoNet network has reported two further earthquakes greater than magnitude 4.0 to have occurred in the region since the 6.0 Mw earthquake.
Emerging information from Christchurch reports a masonry collapse at the remnants of Christchurch Cathedral and fallen masonry from other buildings in the central business district (CBD). The ‘red zone’ within the CBD (as designated following February’s earthquake) is closed and is likely to remain closed for at least the next 24 hours. Limited damage reports are emerging from the suburb of Merivale, whilst damage has also been reported from Lytttelton. Significant rockfalls have been reported in the suburb of Sumner and part of Banks Peninsula. Liquefaction has been reported in Burwood in the northeast of the city, while local media reports are also reporting significant liquefaction in the eastern suburbs. Approximately 50,000 people in the region lost power during the earthquake, and the city’s water infrastructure has been affected. Christchurch airport was temporarily evacuated following the earthquake, as were shopping centres and office blocks through the city.
The earthquakes come within four months of the magnitude 6.3 earthquake that struck the region on February, 21. The USGS has reported that Monday’s earthquakes are a continuing part of the earthquake sequence that initiated with the Darfield earthquake on September, 3, 2010. GeoNet have stated that the 6.0 earthquake is within the range of forecasted aftershocks.
Source : RMS
