Reconstructing the 1867 Keelung Earthquake and Tsunami Based on Historical Documents

• Main Authors: Shih-Nan Cheng, Chen-Fang Shaw, Yeong Tein Yeh
• Format: Article
• Language: English
• Published: Chinese Geoscience Union 2016-06-01
• Series: Terrestrial, Atmospheric and Oceanic Sciences
• Subjects: 1867 Keelung earthquake; Tsunami; Historical document; Shanchiao Fault; Taiwan
• Online Access: http://tao.cgu.org.tw/index.php/articles/archive/geophysics/item/download/2164_ebb376ae29e55e12c3953d7eec0870e2

On 18 December 1867 a disastrous earthquake struck off northern Taiwan and generated a tsunami that caused hundreds of deaths. At that time, with little information available, people could not be expected to identify the mechanism of the1867 Keelung earthquake or the subsequent tsunami. To reconstruct the earthquake and tsunami available historical documents and references were reviewed and verified. The data were then evaluated for its’ credibility. The historical place names were correlated with the present locations and GIS tools were used to reconstruct the earthquake and tsunami and identify the distribution of the resulting damage. Excluding the damage recorded in the Keelung area, there is evidence that shows that the 1867 Keelung earthquake and tsunami killed more than 580 people. The coastal area from Jinshan to Keelung Harbor was the main affected area. With a recorded tsunami wave height of 6 m occurring in Huanggang and Shueiwei, the run-up height in Jinbaoli Old Street and the Badouzi area is estimated to have been 15 m high. The tsunami wave height was observed to be 205 cm at Keelung Harbor Bay. The attenuation law was adopted to simulate the earthquake intensity distribution. The source parameters reasonableness and validity were considered by comparing the earthquake intensity distribution and the resulting damage. Our results show that the 1867 Keelung earthquake was highly correlated with the offshore Shanchiao Fault extension. The length the fault is about 40 km, with the epicenter located at 25.34°N, 121.91°E and focal depth of 10 km. The moment magnitude was 7.0.