Some new research on the Newmark Displacement Method for earthquake-induced landslides indicates that the method may be on the unconservative side. The Landslide Blog provides a short summary of the paper by Li et al. (2018) that was recently published in the journal Landslides. Their research was based on physical models on a shake table, comparing the results of the model experiments with a Newmark analysis. The paper should be worth a read for geotechnical engineers practicing in seismically active areas. It sounds like some additional study is needed to confirm these results and if they are true, propose different ways of analyzing earthquake-induced landslides.
The National Geodetic Data Center (NGDC) of NOAA has an online collection of photos of various geologic hazards. Many of the photos are from older sets of 35mm slides that have been digitized. They are free to use provided you credit the photographer and the NGDC as the source. The would be really useful for educators and for powerpoint presentations. The only drawback is that they are in TIF format and some of them could use some retouching. (Photo by University of Colorado, made available by NOAA/NGDC)