**2. Seismicity and geological background in the vicinity of the Miramichi earthquakes**

The Miramichi earthquake sequence locates in the eastern part of the Appalachian Mountain range (**Figure 1**). The mountain range is mostly in the United States (US). It forms a zone from 160 to 480 km wide, running from the island of Newfoundland southwestward through New Brunswick, Canada to Central Alabama, US. In the north side, past the mountain range, is located the St. Lawrence River. Along this river, the St. Lawrence Faults system developed (e.g., [2]). In the northeast side of the Quebec City, about 100 km away is the Charlevoix seismic Zone (CSZ), which is the most active earthquake zone in eastern Canada. In the history, some destructive earthquakes occurred in the CSZ (seismescanada.rncan.gc.ca/historic-historique/events/18701020-en.php). Adjacent to the CSZ at the northern side is the Saguenay Graben. The 25 November 1988 *Locations of the 1982 Miramichi (Canada) Aftershocks: Implication of Two Rupture Regions… DOI: http://dx.doi.org/10.5772/intechopen.108195*

*M*W 5.9 earthquake occurred along this Graben (e.g., Ma et al., [12]). Downstream from the CSZ, is the Lower St. Lawrence Seismic Zone (LSZ). The largest earthquake detected is the 16 March 1999 mN 5.1 earthquake (e.g., Lamontagne et al., [13]).
