Note:This page contains AI-generated content for informational and entertainment purposes only. It may contain inaccuracies. Raw event data is from USGS and EMSC. All statistics, lists, and derived information are generated by this site. Full disclaimerFound an error?
Location:
60 km W of Poso, Indonesia
Period:
28 Sep 2018 13:39:44 - 29 Sep 2018 10:30:18 (20 hours 50 minutes)
Volcanoes in 100km radius:
None
Earthquakes:
5
7 swarms found nearby.
2005
PS20050124.1(50.9km)
23 Jan
4 hours
5 earthquakes
2017
PS20170529.1(38.4km)
29 May
43 minutes
7 earthquakes
2018
PS20180928.1(157.9km)
28 Sep
7 hours
15 earthquakes
2023
S20230227.1(12.0km)
27 Feb
2 days 0 hours
48 earthquakes
2025
S20250724.2(79.1km)
24 Jul
5 days 15 hours
89 earthquakes
2026
S20260616.1(35.4km)
16 Jun
6 days 20 hours
233 earthquakes
S20260616.2(21.2km)
16 Jun
2 days 0 hours
78 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm PS20180929.1: Analysis of Activity West of Poso, Indonesia

A seismic swarm designated PS20180929.1 occurred approximately 60 km west of Poso in Central Sulawesi, Indonesia. The sequence began at 13:39 on 28 September 2018 and concluded at 10:30 on 29 September 2018, spanning 20 hours and 50 minutes. During this interval, five earthquakes were recorded, each with focal depths of 10 km. Magnitudes ranged from 5.0 to 5.2, with events timed at 13:39:44 (M5.2), 15:35:42 (M5.0), 21:24:01 (M5.0), 07:40:11 on 29 September (M5.1), and 10:30:18 (M5.1).

Swarm sequences such as this reflect clustered seismic energy release without a single dominant mainshock-aftershock pattern. All events shared similar depths and occurred within a compact temporal window, consistent with fluid migration or localized stress adjustments along active fault segments in the region.

Central Sulawesi lies within a tectonically complex zone at the convergence of the Eurasian, Indo-Australian, and Philippine Sea plates. The area experiences frequent seismicity driven by strike-slip motion along the Palu-Koro fault system and associated structures. Historical records document recurrent moderate earthquakes, underscoring the persistent strain accumulation in this part of the Indonesian archipelago.

Since 1 January 2000, three swarms have been identified in the vicinity. Prior episodes occurred in 2005 and 2017, each registering a single swarm event, with the 2018 sequence representing the third instance.

The 2018 activity aligns with the broader seismic character of Sulawesi, where shallow crustal earthquakes predominate due to the island’s position along the Pacific Ring of Fire. Depths around 10 km indicate rupture within the upper crust, typical for strike-slip regimes in this setting.

References

USGS Earthquake Catalog
Global CMT Project
Indonesian Meteorological, Climatological, and Geophysical Agency (BMKG) annual reports