Reviewed by USGSNorthern Mariana Islands31y ago
M4.5 earthquake in Pagan region, Northern Mariana Islands
Sunday, August 27, 1995, 18:18:48 UTC · 18.763°N, 145.464°E
A magnitude 4.5 earthquake struck in Pagan region, Northern Mariana Islands on Sunday, August 27, 1995, 18:18:48 UTC, at a depth of 225.1 km (intermediate). It is the strongest earthquake within 300 km since an M5.4 on August 25, 1995.
- Magnitude
- 4.5
- Light · mb
- Depth
- 225 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 earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
85 tons of TNT
That is about 1/178 of the Hiroshima bomb. A magnitude 5.0 releases about 6 times more energy.
Tectonic setting
91 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
225 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 lists 2 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.3 on August 30, 1995. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 256 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.7Mariana Islands regionDecember 28, 1940 · 220 km E of this epicenter
- 7.2Pagan region, Northern Mariana IslandsOctober 24, 1930 · 134 km E of this epicenter
- 7.1Pagan region, Northern Mariana IslandsAugust 23, 1995 · 28 km W of this epicenter
- 6.9Maug Islands region, Northern Mariana IslandsMarch 7, 1962 · 49 km NW of this epicenter
- 6.7Pagan region, Northern Mariana IslandsNovember 15, 1954 · 39 km NE of this epicenter
- 6.7Pagan region, Northern Mariana IslandsFebruary 1, 1956 · 48 km W of this epicenter
- 6.7Mariana Islands regionSeptember 16, 1986 · 111 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 1 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1902M8.1
Agana
22 Sep 1902 · 102 km away · intensity IX
Severe damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.