Just try to do a change detection on a high resolution satellite data it should be effective.

I don't know if there are simple methods in the field. On the other hand, I agree with Saif that landslides can be monitored by using remote sensing. Mainly radar data are appropriate. For example, you might be interested to look for the activities undertaken at the German Space Agency (DLR) on TerraSAR data. The methods are rather complicated, but reliable.

Dear Zhijie

I think that you need two data sets before and after the landslide.aerial photographs or satellite images to be incorporated with GIS. The use of spatial analysis in GIS.

Dear Zhijie,

There are several ways to detect and monitor landslide. You can use field survey, ground truth and remote sensing (passive and active system) to identify and study landslides. Each methods have limitations. As I understood you, you would like to learn how to detect landslide in field observation.

For this reason, you can check list of indicators of landslide. I found the list from R.Thomas is useful. However, there are more surface signs which can indicate active slope movement. For instance, new ponds, springs, tilted trees, fresh scarps, pressure ridges. I would like to suggest you to find photos or patterns of the landslide structures for the known landslides and use them for your orientation when you are in field trip.

I would like to suggest you to check optical images (for instance in google Earth) for area where you are going. Some landslide indicators are clear from remote sensing observations.

Also, I would like to comment answer from Ruxandra Vintila. InSAR methods can be good techniques to detect and investigate a landslide area. However, they have several limitations, which are not allow to indicate any kind of landslides.

I hope my answer will help you.

Best regards,

Elena

If the objective is only to identify the landslided areas then the arial photographs can help

however, to investigate the geomaterial at teh landslide. field tests are inportant, such as penetration test, seismic refraction. etc.