Reviewed by USGSPhilippines9y ago
M6.9 earthquake 31 km SW of Burias, Philippines
Friday, April 28, 2017, 20:23:17 UTC · 5.504°N, 125.066°E
A magnitude 6.9 earthquake struck 31 km SW of Burias, Philippines on Friday, April 28, 2017, 20:23:17 UTC, at a depth of 26.0 km (shallow). USGS received 115 “Did You Feel It?” reports, with a maximum reported intensity of VII (very strong). The USGS PAGER alert is green: low likelihood of casualties and damage. It is the strongest earthquake within 300 km since an M7.3 on January 10, 2017.
Tsunami flagUSGS sets this flag for large events in oceanic regions so tsunami warning centers review them. It does not by itself mean a tsunami occurred. Check tsunami.gov and local authorities for official messages.
- Magnitude
- 6.9
- Strong · mww
- Depth
- 26 km
- Shallow
- Felt reports
- 115
- Max intensity VII
- Est. shaking
- VI
- Strong (ShakeMap)
- PAGER alert
- Green
- Impact estimate
- Tsunami
- Flag
- Check tsunami.gov
Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
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
263 km
from the nearest mapped plate boundary, between the Philippine Sea and Sunda plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
26 km
Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.
Did You Feel It?
Where it was felt
Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.
| Place | Intensity | Reports | Distance |
|---|---|---|---|
| Davao, Southern Mindanao, Philippines | IV · Light | 34 | 190 km |
| Katangawan, Southern Mindanao, Philippines | VI · Strong | 8 | 79 km |
| Buayan, Southern Mindanao, Philippines | V · Moderate | 8 | 74 km |
| Zamboanga, Western Mindanao, Philippines | IV · Light | 5 | 366 km |
| San Jose (General Santos City, South Cotabato), Southern Mindanao, Philippines | VII · Very strong | 3 | 72 km |
| Pangyan, Southern Mindanao, Philippines | VI · Strong | 3 | 41 km |
| Limao, Southern Mindanao, Philippines | V · Moderate | 3 | 188 km |
| Koronadal, Southern Mindanao, Philippines | V · Moderate | 3 | 115 km |
| Silway, Southern Mindanao, Philippines | V · Moderate | 3 | 79 km |
| Tinagacan, Southern Mindanao, Philippines | VI · Strong | 2 | 83 km |
| Malungon, Southern Mindanao, Philippines | V · Moderate | 2 | 92 km |
| Barra, Northern Mindanao, Philippines | III · Weak | 2 | 335 km |
USGS PAGER estimate
Who was exposed to shaking
Modelled from the ShakeMap and population data. Alert level green: low likelihood of casualties and damage.
- VII · Very strong shaking
- 65,000 people
- VI · Strong shaking
- 488,000 people
- V · Moderate shaking
- 2.0 million people
- IV · Light shaking
- 7.4 million people
- III · Weak shaking
- 16 million people
- II · Weak shaking
- 16 million people
After the main event
Aftershocks within 100 km
USGS lists 9 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M4.7 on April 29, 2017. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.453 km SW of Balangonan, Philippines9y ago · 26 km SW of this epicenter
- 4.434 km SSW of Katubao, Philippines9y ago · 35 km W of this epicenter
- 4.54 km NNW of Mangili, Philippines9y ago · 90 km NE of this epicenter
- 4.440 km S of Daliao, Philippines9y ago · 17 km W of this epicenter
- 4.441 km S of Daliao, Philippines9y ago · 19 km W of this epicenter
- 4.349 km WSW of Balangonan, Philippines9y ago · 18 km SW of this epicenter
- 4.749 km SW of Balangonan, Philippines9y ago · 22 km SW of this epicenter
- 4.346 km WSW of Balangonan, Philippines9y ago · 17 km SW of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 1,561 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.31918 Mindanao, Philippines EarthquakeAugust 15, 1918 · 119 km W of this epicenter
- 8.11924 Mindanao, Philippines EarthquakeApril 14, 1924 · 174 km NE of this epicenter
- 8.01972 Mindanao, Philippines EarthquakeDecember 2, 1972 · 205 km NE of this epicenter
- 7.919 km WNW of Palimbang, PhilippinesAugust 16, 1976 · 143 km NW of this epicenter
- 7.947 km ESE of Kalbay, PhilippinesMarch 14, 1913 · 91 km E of this epicenter
- 7.8161 km SE of Sarangani, PhilippinesApril 1, 1936 · 200 km SE of this epicenter
- 7.7228 km SW of Sarangani, PhilippinesJune 11, 1972 · 215 km SW of this epicenter
- 7.6101 km SE of Sarangani, PhilippinesDecember 16, 1910 · 141 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 39 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 11,120 recorded deaths. The most severe:
- 1976M8.0
Mindanao: S
16 Aug 1976 · 139 km away · intensity VI
8,000 deaths$134 million damagetsunami
- 1856
Sangihe Pulau (Volcanic)
2 Mar 1856 · 210 km away
2,806 deathsSevere damage ($5–24M)tsunami
- 1913M7.8
Sangihe Island
14 Mar 1913 · 118 km away · intensity IX
138 deathsModerate damage ($1–5M)tsunami
- 1928M7.4
Cotabato,N Coast Of Illana Bay
19 Dec 1928 · 162 km away · intensity VII
97 deathsModerate damage ($1–5M)tsunami
- 1918M8.3
Mindanao: Cotabato
15 Aug 1918 · 119 km away · intensity X
52 deathsSevere damage ($5–24M)tsunami
- 2002M7.5
Mindanao
5 Mar 2002 · 108 km away
15 deaths$2 million damagetsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.