{"id":17758,"date":"2016-02-15T07:00:55","date_gmt":"2016-02-15T07:00:55","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=17758"},"modified":"2016-02-14T21:12:44","modified_gmt":"2016-02-14T21:12:44","slug":"sumner-rockfalls-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2016\/02\/15\/sumner-rockfalls-1\/","title":{"rendered":"Sumner rockfalls – videos from the M=5.7 earthquake near Christchurch yesterday"},"content":{"rendered":"
Sumner rockfalls<\/h5>\n

The M=5.7 earthquake in Christchurch, New Zealand yesterday triggered a new set of rockfalls in the Sumner area to the south of the city.\u00a0 These Sumner rockfalls occurred on the same cliffs that were subjected to repeated collapses in the 2011-12 Christchurch earthquake sequence.\u00a0 I have posted images of these rockfalls previously<\/a>, and there has always been concern that there would be further collapses on the cliffs to the south of the city<\/a> as a result of further aftershocks or intense rainfall.<\/p>\n

The earthquake is well-described in a press release put out by Geonet<\/a>:<\/p>\n

A magnitude 5.7 earthquake has occurred at 1:13 pm New Zealand time, 15 km east of Christchurch<\/a>\u00a0\u00a0approximately\u00a015 km deep. So far we have received 2974 felt reports from Hawke’s Bay to Invercargill as at 6:30 pm. The highest level of impact from our felt reports so far has been\u00a0MMI 8<\/a> in central and Christchurch. This is also shown in the coloured Shake Map … which models shaking intensity in Modified Mercalli Intensity<\/a>.<\/p><\/blockquote>\n

This is the Shake Map that Geonet have posted<\/a>.\u00a0 Expect this to be updated in the days ahead, but it shows that parts of the Christchurch area were subjected to quite intense shaking:<\/p>\n

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Geonet<\/a> shakemap from the M=5.7 earthquake off the cost of Christchurch on Sunday<\/p><\/div>\n

.<\/p>\n

\"Sumner

Geonet<\/a> map showing felt reports in the Christchurch area<\/p><\/div>\n

.<\/p>\n

As usual the felt reports correlate well with the shaking intensity map.\u00a0 The Sumner area was subjected to strong shaking, triggering the Sumner rockfalls.\u00a0 The timing of the earthquake was perfect for the collection of videos – it occurred on a Sunday afternoon in the summer vacation on a sunny day near to the beach.\u00a0 In consequence several people captured videos and photos of the Sumner rockfalls.\u00a0 The best photo is this one I think, taken by RNZ \/ Sally Murphy<\/a>, shows the rockfalls in action.\u00a0 Note that the images shows multiple streams of shallow rockslides and rockfalls, all generating large amounts of dust:<\/p>\n

\"Sumner

Sumner rockfalls by RNZ\/ Sally Murphy<\/a><\/p><\/div>\n

.<\/p>\n

There is a host of videos on Youtube showing the immediate aftermath of the rockfalls.\u00a0 Three of the best examples are as follows:<\/p>\n