Reviewed by USGSGuam29y ago
M4.8 earthquake 40 km N of Yigo Village, Guam
Wednesday, May 21, 1997, 05:04:24 UTC · 13.897°N, 144.867°E
A magnitude 4.8 earthquake struck 40 km N of Yigo Village, Guam on Wednesday, May 21, 1997, 05:04:24 UTC, at a depth of 136.5 km (intermediate). It is the strongest earthquake within 300 km since an M6.0 on May 9, 1997.
- Magnitude
- 4.8
- Light · mb
- Depth
- 137 km
- Intermediate
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquake
In context
How big was it, and why here?
Energy released
239 tons of TNT
That is about 1/63 of the Hiroshima bomb. A magnitude 5.0 releases about 2 times more energy.
Tectonic setting
98 km
from the nearest mapped plate boundary, between the Philippine Sea and Mariana plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: intermediate
137 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
Did You Feel It?
Where it was felt
No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.
I felt it — report to USGS ↗USGS PAGER estimate
Who was exposed to shaking
USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.
After the main event
Aftershocks within 50 km
USGS has not published any M2.5+ earthquake within 50 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 401 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.832 km S of Inarajan Village, GuamAugust 8, 1993 · 102 km S of this epicenter
- 7.0176 km ESE of San Jose Village, Northern Mariana IslandsMay 18, 1913 · 243 km E of this epicenter
- 7.098 km SSE of Inarajan Village, GuamDecember 9, 1909 · 166 km S of this epicenter
- 7.032 km NNE of Yigo Village, GuamOctober 26, 1912 · 13 km SE of this epicenter
- 6.549 km N of Yigo Village, GuamApril 23, 1997 · 11 km N of this epicenter
- 6.5112 km NE of Saipan, Northern Mariana IslandsJune 6, 1993 · 283 km NE of this epicenter
- 6.446 km ENE of Yigo Village, GuamOctober 29, 1936 · 46 km E of this epicenter
- 6.3146 km WSW of Merizo Village, GuamNovember 24, 1917 · 201 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 10 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1993M7.8
Tuman Bay, Apra Harbor
8 Aug 1993 · 102 km away · intensity IX
$250 million damagetsunami
- 1849M7.5
Guam
25 Jan 1849 · 169 km away · intensity IX
Severe damage ($5–24M)tsunami
- 1909M8.0
Guam
9 Dec 1909 · 156 km away · intensity VIII
Moderate damage ($1–5M)tsunami
- 1892M7.5
Guam
16 May 1892 · 169 km away · intensity VIII
Moderate damage ($1–5M)tsunami
- 1825
Ladrones Island
Apr 1825 · 169 km away · intensity VIII
Moderate damage ($1–5M)tsunami
- 1834
Agana
May 1834 · 169 km away
Moderate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.