Back-Projection Imaging of Earthquakes

Back-projection analysis of earthquakes is a type of array processing that images the source of seismic waves coherently recorded at stations throughout the seismic network. The method was developed following the magnitude 9.2 Sumatra-Andaman earthquake in 2004. Although properties of earthquakes have been investigated using array data prior to the introduction of the back-projection method, this technique differs from other approaches because it makes limited assumptions and allows detailed and complex rupture propagation to be examined. These advantages have led several researchers to apply the method to many of the largest earthquakes to occur this century. The method has also been effective for the detection of smaller events. A critical component of the success of back-projection has been the development of large-scale, dense seismic arrays. Further improvements and future applications of the method will depend greatly on the continued maintenance and development of these networks.