Written records of historical tsunamis in the northeastern South China Sea – challenges associated with developing a new integrated database

Abstract

Abstract. Comprehensive analysis of 15 previously published regional databases incorporating more than 100 sources leads to a newly revised historical tsunami database for the northeastern (NE) region of the South China Sea (SCS) including Taiwan. The validity of each reported historical tsunami event listed in our database is assessed by comparing and contrasting the information and descriptions provided in the other databases. All earlier databases suffer from errors associated with inaccuracies in translation between different languages, calendars and location names. The new database contains 205 records of "events" reported to have occurred between AD 1076 and 2009. We identify and investigate 58 recorded tsunami events in the region. The validity of each event is based on the consistency and accuracy of the reports along with the relative number of individual records for that event. Of the 58 events, 23 are regarded as "valid" (confirmed) events, three are "probable" events and six are "possible". Eighteen events are considered "doubtful" and eight events "invalid". The most destructive tsunami of the 23 valid events occurred in 1867 and affected Keelung, northern Taiwan, killing at least 100 people. Inaccuracies in the historical record aside, this new database highlights the occurrence and geographical extent of several large tsunamis in the NE SCS region and allows an elementary statistical analysis of annual recurrence intervals. Based on historical records from 1951–2009 the probability of a tsunami (from any source) affecting the region in any given year is relatively high (33.4%). However, the likelihood of a tsunami that has a wave height >1 m, and/or causes fatalities and damage to infrastructure occurring in the region in any given year is low (1–2%). This work indicates the need for further research using coastal stratigraphy and inundation modeling to help validate some of the historical accounts of tsunamis as well as adequately evaluate the recurrence intervals of tsunamis along the now heavily developed coastlines of the region.

Occurrence of 1 ka-old corals on an uplifted reef terrace in west Luzon, Philippines: Implications for a prehistoric extreme wave event in the South China Sea region

“…Radiocarbon and 230 Th/ 234 U dating of coral microatolls (0.8 m amsl) at Paraoir site reveal ages that range from 1.5 to 1.1 ka (Hosono 2003;Abigania 2011). However, recent analysis of historical tsunamis in written records and regional databases of the SCS region still present challenges in evaluating the validity of past tsunami events (Mak and Chan 2007;Lau et al 2010). …”

Tsunami Folklore and Possible Tsunami Source on the Eastern Coast of Taiwan

“…There is no record of a tsunami in the 19 th century in the area. If the Malaulau story occurred in the late 18 th century, it can be related to the 1781 tsunami that was recorded in historical documents (Yu 1981;Hsu and Lee 1996;Mak and Chan 2007;Lau et al 2010). However, the tsunami amplitude caused by a Manila trench earthquake is small along most of the eastern coast of Taiwan, except Ilan ).…”

“…Based on historical documents, Ma and Lee (1997) calculated numerical simulations of tsunamis caused by large earthquakes around Taiwan. Recently, Mak and Chan (2007) and Lau et al (2010) revised historical tsunami databases for Taiwan and the South China Sea using numerous historical documents in which several tsunamis were reported as causing more than several fatalities in Taiwan. After the mid-18 th century, the wave events in 1781 in southern Taiwan and in 1878 off northern Taiwan are associated with large tsunamis.…”

Precise Positioning of BDS, BDS/GPS: Implications for Tsunami Early Warning in South China Sea

“…Despite the absence of clear historical evidence on large tsunamis generated at the Manila trench, tsunami deposits found at the Xischa Islands (~1024 AD) may be attributed to a large event in this source region [34]. According to the recently compiled historical tsunami database for the northeastern South China Sea [35], annual probability of a tsunami in this region from any source is very high (~33%). However, the likelihood of a damaging tsunami per year is much smaller (1%-2%).…”