Reviewed by USGSNew Zealand28y ago
M6.9 earthquake in Kermadec Islands, New Zealand
Thursday, July 9, 1998, 14:45:39 UTC · 30.487°S, 178.994°W
A magnitude 6.9 earthquake struck in Kermadec Islands, New Zealand on Thursday, July 9, 1998, 14:45:39 UTC, at a depth of 129.5 km (intermediate). It is the strongest earthquake within 300 km since an M7.0 on September 20, 1997.
- Magnitude
- 6.9
- Strong · mwc
- Depth
- 130 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: 100 km aftershock search area
In context
How big was it, and why here?
Energy released
338 kilotons of TNT
That is about 22 times the Hiroshima bomb. It released about 708 times the energy of a magnitude 5.0.
Tectonic setting
25 km
from the nearest mapped plate boundary, between the Kermadec and Australian plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: intermediate
130 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 100 km
USGS lists 3 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M4.8 on July 10, 1998. 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 1,208 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.21917 Kermadec Islands, New Zealand EarthquakeMay 1, 1917 · 237 km E of this epicenter
- 8.01976 Kermadec Islands, New Zealand EarthquakeJanuary 14, 1976 · 263 km NE of this epicenter
- 7.5Kermadec Islands, New ZealandNovember 16, 1917 · 132 km NE of this epicenter
- 7.3Kermadec Islands regionSeptember 14, 1959 · 252 km NE of this epicenter
- 7.3Kermadec Islands, New ZealandMarch 26, 1963 · 138 km NE of this epicenter
- 7.3Kermadec Islands, New ZealandJuly 25, 1968 · 88 km SE of this epicenter
- 7.2Kermadec Islands, New ZealandFebruary 9, 1978 · 158 km E of this epicenter
- 7.2Kermadec Islands, New ZealandJuly 3, 1995 · 196 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 9 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1976M7.9
Kermadec Islands
14 Jan 1976 · 208 km away
Limited damage (under $1M)tsunami
- 1968M7.3
S Of, Raoul
25 Jul 1968 · 67 km away
Limited damage (under $1M)tsunami
- 1917M8.0
Kermadec Islands
1 May 1917 · 240 km away
tsunami
- 1976M7.8
Kermadec Islands
14 Jan 1976 · 181 km away · intensity VIII
- 1959M7.7
Kermadec Islands
14 Sep 1959 · 293 km away
- 1978M7.7
S Of
9 Feb 1978 · 158 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.