Tumbi Quarry landslide: was it caused by rainfall or seismic activity?

A paper by Robbins et al. 2013, reviews the landslide that occurred on January 24, 2012 in the Tagali Valley, Southern Highlands Province, Papua New Guinea (PNG). The fatal consequences of the landslide near the Tumbi Quarry, led to another investigation of the event.

As most landslides in PNG are caused either by rainfall or seismic activity, the paper focuses on these two factors in particular. It concentrates on the assessment of rainfall patterns in the area compared to rainfall accumulations obtained for previous failures as well as the evaluation of seismic motion. According to the paper, the landslide was not caused by the seismic activity in the area but by the heavy rain 2 weeks prior to the incident, as well as the intense rainfall 3 months before that. Additional anthropogenic factors in the adjacent region along with the geometry of the deep slope, as shown in the cross-section of the site, could have caused a significant decrease in slope stability.

Source: blogs.agu.org, link.springer.com