M5.5 earthquake 56 km ESE of Yilan, Taiwan
A magnitude 5.5 earthquake struck 56 km ESE of Yilan, Taiwan on Fri, Sep 20, 1985, 11:01 PM GMT+8 (15:01 UTC), 18 km (11 mi) below the surface.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 5.5 (Mw, moment), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 1985-09-20 15:01:23 UTC
- Depth
- 18.4 km (11.4 mi), shallow
- Epicenter
- 24.593° N, 122.280° E
- Region
- Taiwan
- Strongest shaking
- IV, light shaking
- Tsunami flag
- No
- Status
- Reviewed by a seismologist
Magnitude estimates
Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.
| Mag. | Scale | Computed by | Notes |
|---|---|---|---|
| 5.5 | Mw, moment | USGS National Earthquake Information Center | Preferred · Reviewed |
| 5.44 | Mw, moment | ISC-GEM global catalog | Final · ±0.1 |
| 5.4 | Mwc, centroid moment | Global CMT project | Preliminary |
What happened
The USGS’s account of the effects of this earthquake.
Felt on northeastern Taiwan. CENTROID, MOMENT TENSOR (HRV) Data Used: GDSN L.P.B.: 10S, 19C Centroid Location: Origin Time 15:01:22.6 0.4 Lat 24.42N 0.05 Lon 122.20E 0.08 Dep 10.0 FIX Half-duration 1.7 Moment Tensor; Scale 10**24 D-CM Mrr=-1.42 0.10 Mtt=1.47 0.08 Mff=-0.05 0.15 Mrt=1.06 0.38 Mrf=0.18 0.20 Mtf=-0.01 0.08 Principal Axes: (T) Val=1.82 Plg=18 Azm=358 (N) Val=-0.04 Plg=5 Azm=267 (P) Val=-1.78 Plg=71 Azm=162 Best Double Couple:Mo=1.8*10**24 NP1:Strike=96 Dip=27 Slip=-79 NP2:Strike=264 Dip=63 Slip=-95
From the USGS event page for usp0002jy9. U.S. Geological Survey text and figures are in the public domain.
Shaking
The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.
- Strongest estimated
- IV, light shaking
- Peak ground acceleration
- 3.1% of gravity
- Peak ground velocity
- 0.8 cm/s
- Map
- Automatic
Did you feel it?
No one has reported feeling this quake to the USGS.
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 2.5 and up: 12 in the 60 days after this one and 8 in the 30 days before it.
After
- 4.224 km E of Yilan, Taiwan · 14976 days ago · 10 km deep · 32 km away
- 4.421 km NE of Hualien City, Taiwan · 14957 days ago · 33 km deep · 75 km away
- 4.251 km NE of Hualien City, Taiwan · 14955 days ago · 20 km deep · 45 km away
- 4.438 km SSE of Yilan, Taiwan · 14954 days ago · 11 km deep · 45 km away
- 4.017 km W of Yonakuni, Japan · 14954 days ago · 93 km deep · 57 km away
- 4.149 km ESE of Yilan, Taiwan · 14952 days ago · 10 km deep · 9 km away
- 5.243 km E of Yilan, Taiwan · 14948 days ago · 84 km deep · 25 km away
- 4.711 km S of Yonakuni, Japan · 14946 days ago · 52 km deep · 78 km away
- 4.825 km E of Yilan, Taiwan · 14942 days ago · 90 km deep · 32 km away
- 4.766 km SE of Yilan, Taiwan · 14942 days ago · 27 km deep · 27 km away
- 4.25 km SE of Hualien City, Taiwan · 14934 days ago · 22 km deep · 98 km away
- 4.879 km E of Hualien City, Taiwan · 14931 days ago · 18 km deep · 68 km away
Before
- 4.049 km ESE of Yilan, Taiwan · 14990 days ago · 10 km deep · 15 km away
- 4.972 km SW of Yonakuni, Japan · 14997 days ago · 35 km deep · 78 km away
- 5.114 km NW of Yonakuni, Japan · 15000 days ago · 106 km deep · 62 km away
- 3.820 km N of Yonakuni, Japan · 15009 days ago · 33 km deep · 71 km away
- 3.745 km SE of Yilan, Taiwan · 15011 days ago · 28 km deep · 30 km away
- 4.554 km ESE of Yilan, Taiwan · 15012 days ago · 10 km deep · 8 km away
- 4.668 km ENE of Hualien City, Taiwan · 15012 days ago · 43 km deep · 50 km away
- 4.152 km WNW of Yonakuni, Japan · 15015 days ago · 10 km deep · 24 km away
Earthquakes todayTaiwan earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp0002jy9 (also filed as gcmtb092085a, gcmt19850920150125, iscgem516215). Read Mon, Oct 5, 2026, 11:50 AM UTC.