Chronological evidence and significance of Late Pleistocene activity in the Dongshan segment of the eastern branch of the Changle-Zhao'an fault belt

Abstract

Objective The Changle-Zhao'an fault zone is one of the primary active faults running along the coast of the Fujian Province. This fault zone has induced several destructive earthquakes and is thus a principal seismogenic structure in the Fujian Province. Therefore, tight constraints on the Late Quaternary activity of the Changle-Zhao'an fault zone has significant significance. Methods Based on field survey along the Dongshan segment of the eastern branch of the Changle-Zhao'an fault in the Dongshan County, Fujian Province, the timing for the motion of this fault portion was determined to be between (34.8±8.3) ka and (48.0±3.5) ka by using K-feldspar luminescence dating of the strata above the fault break point and footwall. Results This indicates that the fault remained active since the Late Pleistocene. Furthermore, we estimated the potential maximum seismicity along the fault using the empirical relationship between magnitude (M) and fault dislocation (D). Conclusion Determination of a Late Pleistocene active fault, along with the estimate of the maximum earthquake magnitude, provides precise chronological evidence for understanding the activity of the Changle-Zhao'an fault zone. Our results thus serves as an important basis for conducting urban safety assessments in Dongshan County.

Keywords

• changle-zhao'an fault belt
• late pleistocene
• active fault
• osl dating
• chronology
• seismic capacity
• dongshan