Potential Landslides

View the estimate of landslide distribution and potential from the Nowicki Jessee (2017) model and the most recent ShakeMap.

Results show where landslides are most likely to have occurred, providing an estimate of the the proportion of each cell affected by landslides (areal coverage), but the generally coarse topography and geology input data available at global scale preclude site-specific assessment of impacts and limit the accuracy of the model. Ground motion inputs from ShakeMap generally improve with time as additional observations and estimates of fault rupture extent are included in successive versions. Because the distribution and intensity of ground motion greatly influence co-seismic landslide occurrence, improvements in ground motion estimates likewise improve the landslide results.

Reference: Nowicki Jessee, M.A., 2017, An Investigation of Seismic Hazard: Using Geophysical Data to Predict the Location and Impact of Earthquake-induced Landslides Around the Globe and to Estimate Earthquake Potential in the Philippines: Ph.D. dissertation, Indiana University.

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely science to assess ongoing hazards. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

Tectonic Summary

The February 25, 2018, M 7.5 earthquake occurred as the result of thrust faulting at shallow a depth. Preliminary focal mechanism solutions indicate slip occurred on either a moderately dipping fault striking west-northwest, or on a moderately dipping fault striking southeast. At the location of this earthquake, the Australia plate is converging with the Pacific plate, moving towards the east-northeast with respect to Pacific lithosphere at a velocity of approximately 107 mm/yr. Earthquakes in this geographical region are generally associated with the large-scale convergence of these two major plates, and with the complex interactions of several associated microplates, most notably the South Bismarck plate, the Solomon Sea microplate, and the Woodlark plate. The location, depth, and focal mechanism solution of this earthquake are consistent with it occurring as intraplate faulting within the crust of the Australia plate.

While commonly plotted as points on maps, earthquakes of this size are more appropriately described as slip over a larger fault area. Thrust-faulting events of the size of the February 25th, 2018 earthquake are typically about 85x30 km (length x width).

Papua New Guinea experiences a high rate of seismic activity, with 23 other events of M 6+ occurring within 250 km of the February 25, 2018 earthquake over the preceding century. The closest of these was a M 6.2 earthquake in August 1993, about 17km to the north of today's earthquake. The largest was a M 7.2 event in June 1986, 230 km to the north-northeast on or near the Australia:Pacific plate boundary in the region. With the exception of a M 7.5 earthquake at intermediate depth (186 km) in eastern Papua New Guinea in February 1963 (which occurred on the subduction zone at depth), all prior M 7.5+ earthquakes in this region have been associated with the shallow subduction zone plate boundaries in northern New Guinea. The vast majority of moderate-to-large earthquakes in this region are not known to have caused significant damage or casualties, though few have been as large as today's earthquake. A M 7.1 earthquake in June 1976, 340 km to the northeast of this event, resulted in over 400 shaking related deaths. Landsliding also caused a significant number of additional fatalities in that event.

Event Details

Event Map

Tectonic Summary

Tectonic Summary

Historical Magnitude 4.5+ (100km)