Reviewed by USGSEcuador66y ago
M6.6 earthquake 119 km E of Macas, Ecuador
Friday, July 28, 1961, 01:05:31 UTC · 2.287°S, 77.035°W
A magnitude 6.6 earthquake struck 119 km E of Macas, Ecuador on Friday, July 28, 1961, 01:05:31 UTC, at a depth of 142.1 km (intermediate). It is the strongest earthquake within 300 km since an M7.5 on September 28, 1906.
- Magnitude
- 6.6
- Strong · mw
- Depth
- 142 km
- Intermediate
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- V
- Moderate (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
108 kilotons of TNT
That is about 7 times the Hiroshima bomb. It released about 226 times the energy of a magnitude 5.0.
Tectonic setting
205 km
from the nearest mapped plate boundary, between the North Andes and South American plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: intermediate
142 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 has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 8 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.516 km W of Barranca, PeruSeptember 28, 1906 · 281 km S of this epicenter
- 6.542 km SE of Cayambe, EcuadorMay 11, 1955 · 247 km N of this epicenter
- 6.522 km NE of Baños, EcuadorAugust 5, 1949 · 183 km NW of this epicenter
- 6.3128 km ESE of Palora, EcuadorJune 12, 1942 · 29 km NE of this epicenter
- 6.233 km W of Ambato, EcuadorJuly 22, 1924 · 239 km NW of this epicenter
- 6.280 km ENE of Gualaquiza, EcuadorMay 25, 1958 · 141 km SW of this epicenter
- 6.037 km NW of Archidona, EcuadorJune 10, 1927 · 211 km NW of this epicenter
- 6.0119 km WNW of Barranca, PeruMay 26, 1928 · 262 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 16 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 47,051 recorded deaths. The most severe:
- 1797M8.3
Riobamba, Quito, Cuzco; Peru; Colombia
4 Feb 1797 · 195 km away · intensity XI
40,000 deathsExtreme damage ($25M+)tsunami
- 1949M6.5
Tungurahua
5 Aug 1949 · 183 km away
6,000 deaths$8 million damage
- 1757M7.0
Cotopaxi,Tungurahua, Latacunga
22 Feb 1757 · 232 km away · intensity IX
1,000 deathsSevere damage ($5–24M)
- 1924M6.9
Ecuador
3 Mar 1924 · 190 km away
40 deathsLimited damage (under $1M)
- 1960
Ecuador
30 Jul 1960 · 235 km away
11 deathsLimited damage (under $1M)
- 1938M7.0
Alangasi,Sangolqui,Tingo-Pichincha
10 Aug 1938 · 268 km away · intensity X
Extreme damage ($25M+)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.