Seismic damage to ancient monuments in Chiang Saen (Northern Thailand): implication for historical earthquakes in Golden Triangle area

Abstract

Over the last few decades, three moderate earthquakes (Mw greater than 6.0) occurred in and around the Golden Triangle area (including Myanmar, Thailand and Lao PDR) causing unprecedented damage and loss of lives in the epicentral region. In addition to the damage to modern structures, most heritage structures in Chiang Saen, a major city of the Lan Na kingdom (from the thirteenth to the eighteenth century), were also affected. This work is intended to present observed historical structure damage from recent earthquakes, which could provide evidence for the severity of historical earthquakes from the thirteenth to the eighteenth century. Based on historical records, geological evidence and observed damage to ancient monuments in this historic town, existing heritage stupas and temples constructed since the fourteenth century sustained only minor to moderate damage from these historical earthquakes. Considering the seismic vulnerability of these historical monuments, Chiang Saen might have never been subjected to severe ground shaking greater than MMI intensity VII, similar to the major earthquake in 460 A.D. along the Mae Chan fault, which was responsible for the large-scale liquefaction and inundation of ancient Yonok town. This information could be important for paleoseismological and historical earthquake research to constrain the recurrence interval of major active faults in this area. This article is part of the theme issue ‘Environmental loading of heritage structures’.

Probabilistic seismic hazard assessments for Northern Southeast Asia (Indochina): Smooth seismicity approach

“…For example, if the results of studies are based on recent trenching investigations, those slip rates will be preferred instead of studies based on comparison of geomorphology. In addition, the rates of earthquakes in a fault model determined from the chosen slip rate and M max are directly compared with those observed from the damage or the existence of ancient structures along these faults (Ornthammarath, 2019; Wang et al, 2011). This procedure is intended to prevent estimation of the larger earthquake activity rate than the known historical record.…”