## 3 Literature Review and Comparison of Interferometric Coherence and Intensity Correlation
### Interferometric Coherence  
This Section gives a review of studies on damage assessment methods based on the coherence (_cf._ Section 2.1). [PERSON] _et al._[95], and [PERSON] and [PERSON] [96] applied the coherence ratio to assess the building damage of the 1995 Kobe Earthquake (also known as the Hyogokon-Nanbu Earthquake), Japan. [PERSON] _et al._[95] used both pre- and post-disaster C-band ERS-1 and L-band Japanese Earth  
\begin{table}
\begin{tabular}{|c c c c|} \hline
**Year** & **Earthquake** & **Country** & **Studies** \\ \hline \multirow{6}{*}{1995} & & & [PERSON] _et al._ 2000 [95], [PERSON] and [PERSON] 1999 [76], [PERSON] and [PERSON] 2001 [84], [PERSON] and [PERSON] 2002 [96], [PERSON] and [PERSON] 1999 [97], [PERSON] and [PERSON] 2000 [73], [PERSON] _et al._ 2002 [98], [PERSON] and [PERSON] 2004 [99], [PERSON] and [PERSON] 2005 [101], [PERSON] and [PERSON] 2010 [101] \\ \cline{2-3}  & & & [PERSON] and Yamazaki 2000 [73], [PERSON] and [PERSON] 2002 [102], [PERSON] _et al._ 2003 [103], [PERSON] _et al._ 2010 [104] \\ \cline{2-3}  & & & [PERSON] _et al._ 2004 [7], [PERSON] _et al._ 2006 [78], [PERSON] and [PERSON] 2009 [105], [PERSON] _et al._ 2010 [104] \\ \cline{2-3}  & & & \\ \cline{2-3}  & & & \\ \cline{2-3}  & & & \\ \cline{2-3}  & & & \\ \cline{2-3}  & & & \\ \cline{2-3}  & & & \\ \cline{2-3}  & & & \\ \cline{2-3}  & & & \\ \cline{2-3}  & & & \\ \cline{2-3}  & & & \\ \cline{2-3}  & & & \\ \cline{2-3}  & & & \\ \hline \end{tabular}
\end{table}
Table 3: Severe earthquakes and published research focusing on SAR imagery.  
Resources Satellite (JERS-1) SAR imagery for their damage assessment approach. The authors found that due to the longer wavelength of JERS-1 its average coherence is higher (with also higher contrast) than that of ERS-1. In [PERSON] _et al._[95] the change (_i.e._, the damage) was detected by using a neural network classification approach. Furthermore, [PERSON] _et al._[103] proposed a post-earthquake damage estimation model based on the coherence ratio. They applied their approach to investigate the damage of the 1999 Kocaeli Earthquake, Turkey, according to the European Macro Scale 1998 (EMS-98) [122].  
[PERSON] _et al._[98] investigated damage assessment of urban area based on coherence using a normalized difference approach (see Equation (10)). They investigated the 1995 Hygokon-Nanbu Earthquake, Japan, using JERS-1 SAR data and the 2001 Gujrat Earthquake, India.  
As already mentioned above, based on pre- and post-event ENVISAT Advanced Synthetic Aperture Radar (ASAR) data, [PERSON] [74] proposed a coherence change index to determine the damage of the 2003 Bam (Iran) Earthquake at the block level (Equation (13)).  
In [PERSON] _et al._[107] a visual interpretation of the interferometric coherence (computed from pre- and post-disaster ENVISAT ASAR imagery) is described to assess the damage after the 2003 Bam Earthquake. The assessment results were compared with ground-truth maps.  
The level of detail of the damage assessment is predefined by the spatial resolution of the SAR sensor used, which is for the methods reviewed in this Section 3.1 the L-band JERS-1 and the C-band ERS and ENVISAT ASAR. The spatial resolution of these SAR sensors is 18 or 30 m, respectively (see Table 2, Section 1.2). Therefore, all aforementioned methods enable damage assessment at the block level. For analysis at this scale we also emphasize the higher contrast of the coherence based on L-band SAR imagery compared to data acquired at C-band [95], which makes change detection (_i.e._, damage detection) a bit easier. As mentioned in Section 2.3, [PERSON] [74] reported good visual correlation of the detected damage with damage maps based on very high spatial resolution optical imagery. However, no quantitative validations of the reviewed damage assessment methods of Section 3.1 were reported.