Significant M5.5 Earthquake struck on Monday Night near Machala in Ecuador.

Written by Earthquakelist.org on August 21st, 2023. Last updated October 19th, 2023.

Under land 7 kilometer from Machala in Ecuador, a significant Magnitude 5.5 earthquake occurred just after midnight of Monday August 21st, 2023. Around 10 million people have been exposed to shaking. Another nearby country is Peru.

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Earthquake Summary

The earthquake struck on land in Ecuador, 7 kilometer (4 mi) east of Machala in El Oro. The center of this earthquake had a quite shallow depth of 61 km. Shallow earthquakes usually have a larger impact than earthquakes deep in the earth.

Date and Time:	Aug 21, 2023 00:24 (Guayaquil Time) - Aug 21, 2023 05:24 Universal Time.
Location:	7 km east of Machala, El Oro, Ecuador. Coordinates 3°15'4"S 79°53'58"W.
Map:	Map of area around epicenter. Click to open in Google Maps.
Magnitude:	MAG 5.5 Detected by 10 stations. Maximum Error Range ±0.098 .
Depth:	61 km (38 mi) A quite shallow depth.
Max. Intensity:	V Moderate On the Modified Mercalli Scale.
Tsunami Risk:	Tsunami very unlikely While this was a shallow earthquake in a coastal area, it appears to have occurred under land (8 km from the sea) with a magnitude that is usually not strong enough to cause tsunami's. Always stay cautious - More info here.

Minimal impact predicted

Based on scientific estimates by the US Geographic Survey (USGS), the risk of high fatalities for this earthquake is classified at level GREEN (low). They expect an 65% likelyhood of between 0 and 1 fatalities, and a 96% chance that the number of fatalities falls no higher than 10.

The USGS classifies the economic impact of this earthquake at level GREEN (low). They expect an 65% likelyhood of between 0 and 1 million US Dollars in economic damage and impact, and a 96% chance that the economic impact of this earthquake falls no higher than 10 million USD.

Roughly 10 million people exposed to shaking

An estimated 10 million have been exposed to shaking (An MMI or Modified Mercalli Intensity level II or higher) as a result of this earthquake according scientific estimates published by the USGS.

The highest earthquake impact level for this earthquake is IV, which corresponds with light shaking and likely no damage. Roughly 2,785,000 people are expected to be exposed to this level. The majority of people (roughly 7.1 million) live in an area exposed to level III, where weak shaking and probably no damage is expected.

People in 2 countries have been exposed to shaking. Roughly 9 million people were exposed to shaking in Ecuador , with level IV (light shaking, likely no damage) as the highest recorded. Roughly 1.2 million people were exposed to shaking in Peru .

Nearby towns and cities

Ecuador and Peru are both located within 300km distance of the epicenter of the earthquake.

Machala in El Oro, Ecuador is the nearest significant place from the epicenter. The earthquake occurred 7 kilometer (4 mi) east of Machala. The intensity of shaking and damage in Machala is estimated to be around level IV on the Modified Mercalli Intensity scale (light shaking, likely no damage).

Multiple large cities are in proximity of today's earthquake. Machala is located 7 km to the west and experienced an intensity of IV (light shaking, likely no damage). Guayaquil is located 117 km to the north and experienced an intensity of III (weak shaking, probably no damage). Cuenca is located 107 km to the east-northeast and experienced an intensity of IV (light shaking, likely no damage).

A complete list of nearby places is included below. Estimated intensity data (MMI) sourced from a shake-map published by the US Geographic Survey is shown where available (cities without data probably experienced little impact).

Overview of nearby places

Earthquake Intensity Map

The graph below overlays a map of the region around the epicenter with earthquake intensity data provided by the US Geographic Survey. The highest intensity level detected for this earthquake is IV.

I Not felt

II Weak

III Weak

IV Light

V Moderate

VI Strong

VII Very Strong

VIII Severe

IX Violent

X Extreme

Shaking reported by 36 people in 2 countries

People that feel an earthquake may report their experience to the US Geographic Survey. Currently, 36 people have reported shaking in 21 places in 2 countries (Ecuador, Peru).We keep updating this article as more ground reports become available. You may report that you felt this earthquake here.

Places with most reports:

• Cuenca, Azuay, Ecuador: 9 people.
• Guayaquil, Guayas, Ecuador: 3 people.
• Tumbes, Tumbes, Peru: 2 people.
• Piura, Piura, Peru: 2 people.
• Loja, Loja, Ecuador: 2 people.
• Santa Lucía, Guayas, Ecuador: 2 people.
• Azogues, Cañar, Ecuador: 2 people.
• Machala, El Oro, Ecuador: 1 person.
• Pasaje, El Oro, Ecuador: 1 person.
• Piñas, El Oro, Ecuador: 1 person.

Aftershocks detected

After this earthquake struck, 1 smaller aftershock occurred. At a distance of 37 km (23 mi) west-northwest of this earthquake, an aftershock struck 4 hrs later. It measured a magnitude of 4

Overview of foreshocks and aftershocks

More earthquakes coming?

Earthquakes can create aftershocks. These are generally at least 1 magnitude lower than any main shock, and as time passes the chance and strength of aftershocks decreases.

In only six percent of cases, significant earthquakes are followed by a larger main shock, making the current earthquake a foreshock. While the chance of this happening is not so large, it is adviced to maintain cautiousness in the hours and days following a major earthquake.

Earthquakes like this happen often in the region

Earthquakes of this strength are very common in the region. This is the strongest earthquake to hit since March 18th, 2023, when a 6.8 magnitude earthquake hit 52 km (32 mi) further north. That was also the heaviest earthquake to hit the region in the past 10 years.

In total, 14 earthquakes with a magnitude of 5.5 or higher have been registered within 300km (186 mi) of this epicenter in the past 10 years. This comes down to an average of once every 9 months.

Tsunami very unlikely

While MAG-6.5+ earthquakes may cause tsunami's, it appears that the epicenter of this earthquake hit under land. In addition, the reported depth is deeper than 100km, making the risk of a tsunami even less likely. However always stay cautious and monitor advice from local authorities.

Tsunami Risk Factors

Sources

Last updated 19/10/23 17:37 (). This article contains currently available information about the earthquake and is automatically composed. We continue to update this article up to a few days after the earthquake occurred.

1. US Geographic Society (USGS): Earthquake us7000kpt4
2. European-Mediterranean Seismological Centre (EMSC): Earthquake 20230821_0000058
3. Geonames.org: World Cities Database
4. Google Maps: Static API
5. Earthquakelist.org: Historic Earthquakes Database

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