How frequent are earthquakes in the area near the epicenter of this quake (within 100 km/61 mi)?

Q: How frequent are earthquakes in the area near the epicenter of this quake (within 100 km/61 mi)?

The area where this quake occurred has a high level of seismic activity. Based on data from the past 54 years and our earthquake archive back to 1900, there are about 2.9 quakes on average per year in the area near the epicenter of this quake (within 100 km/61 mi). It has had at least 2 quakes above magnitude 6 since 1900, which suggests that larger earthquakes of this size occur infrequently, probably on average approximately every 60 to 65 years.

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Very strong mag. 6.0 Earthquake - Mid Indian Ridge on Sunday, Oct 3, 2021, at 12:43 am (GMT +4)

A very strong magnitude 6.0 earthquake occurred in the Indian Ocean near the coast of n/a in the early morning of Sunday, Oct 3, 2021 at 12.43 am local time (GMT +4). The quake had a very shallow depth of 10 km (6 mi) and was not felt (or at least not reported so).

Very strong mag. 6.0 Earthquake - Mid Indian Ridge on Sunday, Oct 3, 2021, at 12:43 am (GMT +4)

Very strong magnitude 6.0 earthquake at 10 km depth

2 Oct 20:53 UTC: First to report: GFZ after 10 minutes.
2 Oct 20:54: Magnitude recalculated from 5.6 to 5.5. Epicenter location corrected by 2.5 km (1.5 mi) towards ESE.
2 Oct 21:02: Magnitude recalculated from 5.5 to 5.9. Epicenter location corrected by 3.3 km (2 mi) towards W.
2 Oct 21:09: Magnitude recalculated from 5.9 to 6.0.

Earthquake details

Date & time	Oct 2, 2021 20:43:39 UTC
Local time at epicenter	Sunday, Oct 3, 2021, at 12:43 am (GMT +4)
Status	Confirmed (manually revised)
Magnitude	6.0
Depth	10 km
Epicenter latitude / longitude	9.22°S / 67.16°EInternational Territory (not near any country)
Seismic antipode	9.22°N / 112.84°W
Shaking intensity	VI Strong shaking near epicenter
Felt	0 reports
Primary data source	GFZ (German Research Centre for Geosciences)
Nearest volcano	###NEARESTVOLCANO2###
Weather at epicenter at time of quake	Few Clouds 26.2°C (79 F), humidity: 71%, wind: 8 m/s (16 kts) from ESE
Estimated seismic energy released	6.3 x 10¹³ joules (17.5 gigawatt hours, equivalent to 15080 tons of TNT or 0.9 atomic bombs!) \| about seismic energy

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Nearby places

The closest larger town where the quake might have been felt is Île Lubine, a town with 15 inhabitants in the British Indian Ocean Territory, in 540 km (336 mi) distance northeast of the epicenter. People likely experienced weak shaking there.
The following table shows some of the places that might have been affected (or not) by the shaking.

Distance	Place	Max. shaking intensity(*)	Region	Country
540 km (336 mi) NE of epicenter	Île Lubine (pop: 15)	III: Weak		British Indian Ocean Territory

Notes:
(*) Shaking intensity according to the Modified Mercalli Intensity Scale (MMI) and estimated using seismic models.

User-reports for this quake (3)

We received 3 reports for this quake.

User reports estimate the perceived ground shaking intensity according to the MMI (Modified Mercalli Intensity) scale.

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Sleeping / not felt : I didn't feel.

Where's Sleeping?

Perth / not felt

Society Hill SC / not felt

What is Intensity and the Mercalli Intensity Scale?

The amount of shaking that occurs on the surface due to an earthquake is called the intensity. It is commonly measured on the so-called Modified Mercalli Intensity Scale (MMI) ranging from 1 (not felt) to 10 (extreme shaking), and given in Roman numerals as I,II,...IX, X, and often displayed with color codes ranging from light blue to dark red.
Earthquake intensity depends mainly on the magnitude and depth of the quake as well as the distance from the epicenter: The further away, the less shaking intensity occurs.
Read more about the MMI scale!

Compare Quake Data

Data for the same earthquake as reported by different agencies

The more agencies report about the same quake and post similar data, the more confidence you can have in the data. It takes normally up to a few hours until earthquake parameters are calculated with near-optimum precision.

Mag	Depth	Time GMT 2021-10-2	Epicenter	Agency
6.0	10 km 6.2 mi (*)	20:43:39	Mid Indian Ridge	GFZ (German Research Centre for Geosciences)
6.0	60 km 37 mi	20:43:45	MID-INDIAN RIDGE 3.3 km (2.1 mi) epicenter difference with GFZ	EMSC (European-Mediterranean Seismological Centre)
5.4	10 km 6.2 mi (*)	20:43:41	Near Port Louis 14 km (8.7 mi) epicenter difference with GFZ	RENASS (Réseau National de Surveillance Sismique (RéNaSS))
5.7	38 km 24 mi	20:43:43	Mid Indian Ridge 12 km (7.4 mi) epicenter difference with GFZ	BMKG (Meteorological, Climatological, and Geophysical Agency of Indonesia)
6.0	10 km 6.2 mi (*)	20:43:40	Mid-Indian Ridge 12 km (7.5 mi) epicenter difference with GFZ	USGS (United States Geological Survey)
5.9	33 km 20 mi	20:43:43	Mid Indian Ridge 2.6 km (1.6 mi) epicenter difference with GFZ	GeoAu (Geoscience Australia )

Notes:
(*) A depth given as 10 km often means that the the depth of the quake could not determined with sufficient accuracy.

Seismograms

Seismic station: Diego Garcia, Chagos Islands, Indian Ocean (DGAR/II network) | Distance from quake: 616 km / 383 mi | Show on map | Station Info

Seismic station Diego Garcia, Chagos Islands, Indian Ocean: vertical movement plot around time of quake (source: IRIS/BUD)

Seismogram (vertical component) around time of quake. Thin dotted red line indicates time of quake. Seismic waves arrive some time later, depending on distance. Bandpass filter applied: 0.02-5.0 Hz. Source: IRIS Buffer of Uniform Data (BUD) webtool

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Seismic station Diego Garcia, Chagos Islands, Indian Ocean: horizontal (E-W) movement plot around time of quake (source: IRIS/BUD)

Seismic station Diego Garcia, Chagos Islands, Indian Ocean: horizontal (N-S) movement plot around time of quake (source: IRIS/BUD)

Seismograms around time of quake, showing horizontal E-W and N-S ground movements. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station: Pallekele, Sri Lanka (PALK/II network) | Distance from quake: 2369 km / 1472 mi | Show on map | Station Info

Seismic station Pallekele, Sri Lanka: vertical movement plot around time of quake (source: IRIS/BUD)

Seismogram (vertical component) around time of quake. Thin dotted red line indicates time of quake. Seismic waves arrive some time later, depending on distance. Bandpass filter applied: 0.02-2.0 Hz. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station Pallekele, Sri Lanka: horizontal (E-W) movement plot around time of quake (source: IRIS/BUD)

Seismic station Pallekele, Sri Lanka: horizontal (N-S) movement plot around time of quake (source: IRIS/BUD)

Seismograms around time of quake.
Top: vertical movement, bottom: horizontal (E-W and N-S) movements. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station: West Island, Cocos (Keeling) Islands (COCO/II network) | Distance from quake: 3257 km / 2024 mi | Show on map | Station Info

Seismic station West Island, Cocos (Keeling) Islands: vertical movement plot around time of quake (source: IRIS/BUD)

Seismogram (vertical component) around time of quake. Thin dotted red line indicates time of quake. Seismic waves arrive some time later, depending on distance. Bandpass filter applied: 0.02-2.0 Hz. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station West Island, Cocos (Keeling) Islands: horizontal (E-W) movement plot around time of quake (source: IRIS/BUD)

Seismic station West Island, Cocos (Keeling) Islands: horizontal (N-S) movement plot around time of quake (source: IRIS/BUD)

Seismograms around time of quake.
Top: vertical movement, bottom: horizontal (E-W and N-S) movements. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station: Univ. of Sharjah, Sharjah, United Arab Emirates (UOSS/II network) | Distance from quake: 3980 km / 2473 mi | Show on map | Station Info

Seismic station Univ. of Sharjah, Sharjah, United Arab Emirates: vertical movement plot around time of quake (source: IRIS/BUD)

Seismogram (vertical component) around time of quake. Thin dotted red line indicates time of quake. Seismic waves arrive some time later, depending on distance. Bandpass filter applied: 0.02-2.0 Hz. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station Univ. of Sharjah, Sharjah, United Arab Emirates: horizontal (E-W) movement plot around time of quake (source: IRIS/BUD)

Seismic station Univ. of Sharjah, Sharjah, United Arab Emirates: horizontal (N-S) movement plot around time of quake (source: IRIS/BUD)

Seismograms around time of quake.
Top: vertical movement, bottom: horizontal (E-W and N-S) movements. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station: Chiang Mai, Thailand (CHTO/IU network) | Distance from quake: 4676 km / 2905 mi | Show on map | Station Info

Seismic station Chiang Mai, Thailand: vertical movement plot around time of quake (source: IRIS/BUD)

Seismogram (vertical component) around time of quake. Thin dotted red line indicates time of quake. Seismic waves arrive some time later, depending on distance. Bandpass filter applied: 0.02-2.0 Hz. Source: IRIS Buffer of Uniform Data (BUD) webtool

Seismic station Chiang Mai, Thailand: horizontal (E-W) movement plot around time of quake (source: IRIS/BUD)

Seismic station Chiang Mai, Thailand: horizontal (N-S) movement plot around time of quake (source: IRIS/BUD)

Seismograms around time of quake.
Top: vertical movement, bottom: horizontal (E-W and N-S) movements. Source: IRIS Buffer of Uniform Data (BUD) webtool

Aftershocks for this quake

No aftershocks have been recorded so far. When aftershocks are detected, we will update this section.

What are aftershocks?

Larger earthquakes (above magnitude 5 or so) such as this one are usually followed by smaller ones known as aftershocks that occur in the same area during the days, weeks, months or even years after the main shock.

[More info]

What about this quake?

Based on its magnitude, the fault that was active during the quake likely ruptured beneath a surface of approx. 100 km² (=39 sqare miles) as a first-order estimate. The length of the rupture zone thus was probably around 17 km (11 mi).

[More info]

Recorded aftershocks, latest first (0 quake)

Date and Time GMT	Mag Depth	Distance	Region	Details
Oct 3, 2021 12:43 am (GMT +4) 3 years ago	6.0 10 km	0 km - This quake	Mid Indian Ridge Main Shock (this quake)	More

Map of aftershocks

Earthquake statistics

Average number of earthquakes

Based on data from the past 54 years and our earthquake archive back to 1900, there are about 2.9 quakes on average per year in the area near the epicenter of this quake (within 100 km/61 mi):

Mag. 6 or higher: 0.02 quakes per year (or 1 quake every 62.5 years)
Mag. 5 or higher: 0.65 quakes per year (or 1 quake every 1.5 years)
Mag. 4 or higher: 1.83 quakes per year
Mag. 3 or higher: 1.83 quakes per year
Mag. 2 or higher: 1.83 quakes per year

The area where this quake occurred has a high level of seismic activity. It has had at least 2 quakes above magnitude 6 since 1900, which suggests that larger earthquakes of this size occur infrequently, probably on average approximately every 60 to 65 years.

Number of quakes per year

Previous quakes in the same area of this earthquake

Map to embed or share

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