『Abstract
　Efficient restoration of deteriorating coastal structures requires an accurate picture of both above ground and underground features. Although ground penetrating radar (GPR) can map underground features, it creates reflection artifacts. Here, a model for deconvolution calibration was developed in an outdoor small-scale experiment. GPR parameters were established, then applied at a deteriorating fishing port in northeast Taiwan. The deconvolution filter removed repetitive reflection patterns under the lowest part of void crating a more accurate map. A 3D-map was created from interpolated sketched void boundaries. Due to its high lossy nature at radar frequencies and large contrasting relative dielectric permittivity (RDP) to the upper medium, the seawater table (SWT) is easily identified. The upper boundary of reflection-free area in the deconvoluted radargram, therefore, indicates the SWT. The methods developed here are easily modified to fit a wide range of situations.

Keywords: Geophysics; Void bottom detection; Deconvolution; Seawater table; Ground penetrating radar; Taiwan』

Introduction
Methodology
　Equipment and processing of deconvolution
　Small-scale test model
　Applying the model to the field
Results
　Small-scale experiment
　　Voids detecting and mapping
　　Evaluating SWT
Discussion
　Identification for void bottom
　3D-void mapping in the Nanfangao site
　Down-shifted frequency in seawater-soaked backfill
Conclusions
Acknowledgments
References