A shallow Magnitude 4.2 earthquake struck under land 6 miles from Watsonville in The United States in the night of Sunday September 29th, 2024. The earthquake struck near a very densely populated region. The USGS has indicated there is a potential risk at tsunami's following this earthquake.
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Earthquake Summary
The earthquake struck on land in The United States, 6 miles (9 km) east of Watsonville in California. The center of this earthquake had a very shallow depth of 4 km. Shallow earthquakes usually have a larger impact than earthquakes deep in the earth.
Date and Time: | Sep 29, 2024 02:47AM (Los Angeles Time) - Sep 29, 2024 09:47 Universal Time. |
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Location: | 6 mi east of Watsonville, California, The United States. Coordinates 36°54'43"N 121°39'12"W. |
Map: | Map of area around epicenter. Click to open in Google Maps. |
Magnitude: | MAG 4.2 Detected by 9 stations. Maximum Error Range ±0.028 . |
Depth: | 4 mi (7 km) A very shallow depth. |
Max. Intensity: | V
Moderate On the Modified Mercalli Scale. |
Tsunami Risk: | Potential tsunami risk The USGS has indicated there is a potential risk at tsunami's following this earthquake. Always stay cautious - More info here. |
Potential tsunami risk
There is a potential tsunami risk in the aftermath of this earthquake, immediately evacuate to higher grounds away from coastal areas and monitor advice from local authorities. The US Geographic Survey organization has indicated a potential risk for tsunami's following this earthquake.
Tsunami Risk Factors
Factor | Under Sea? | MAG-6.5 or stronger? | Shallow depth? |
---|---|---|---|
Explanation | Almost all tsunami's are caused by earthquakes with their epicenter under sea or very near the sea. However stay cautious in coastal areas as earthquakes on land may cause landslides into sea, potentially still causing a local tsunami. | Under MAG 6.5: Very unlikely to cause a tsunami. MAG 6.5 to 7.5: Destructive tsunami's do occur, but are uncommon. Likely to observe small sea level changes. MAG 7.6+: Earthquakes with these magnitudes might produce destructive tsunami's. |
Most destructive tsunami's are caused by shallow earthquakes with a depth between 0 and 100km under the surface of the earth. Deeper tsunami's are unlikely to displace to ocean floor. |
This Earthquake | This earthquake appears to have struck on land near a coastal area (10 mi from the sea). | Not this earthquake. This earthquake had a magnitude of 4.2. Earthquakes of this strength are unlikely to trigger a tsunami. |
This earthquake occurred at a depth of of 4 mi (7 km). Earthquakes this shallow could trigger a tsunami. |
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 9 million people exposed to shaking
An estimated 9 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.
Moderate shaking and very light damage may have been experienced by an estimated 3,390 people. At V, it is the highest MMI level this earthquake has caused. The majority of people (roughly 5.3 million) live in an area exposed to level I, where not noticeable and no damage is expected.
People | MMI Level | Shaking | Damage |
---|---|---|---|
5,313,000 | I |
Not noticable | None |
5,166,000 | II |
Very weak | None |
3,658,000 | III |
Weak | Probably none |
167,400 | IV |
Light | Likely none |
3,390 | V |
Moderate | Very light |
0 | VI |
Strong | Light |
0 | VII |
Very Strong | Moderate |
0 | VIII |
Severe | Moderate to heavy |
0 | IX |
Violent | Heavy |
0 | X |
Extreme | Very heavy |
Nearby towns and cities
This earthquake may have been felt in The United States . Watsonville in California, The United States is the nearest significant place from the epicenter. The earthquake occurred 6 miles (9 km) east of Watsonville. Watsonville experienced an earthquake intensity (MMI Scale) of roughly IV. That level implies light shaking and likely no damage.
Multiple large cities are in proximity of today's earthquake. San Jose is located 32 mi to the north-northwest and experienced an intensity of III (weak shaking, probably no damage). San Francisco is located 73 mi to the northwest and experienced an intensity of III (weak shaking, probably no damage). Salinas is located 16 mi to the south and experienced an intensity of III (weak shaking, probably no damage).
An overview of nearby towns and cities is available in the overview below. If places don't have intensity data available, it likely means the experienced impact in those places was fairly small.
Overview of nearby places
Distance | Place | Intensity (MMI) |
---|---|---|
6 mi (9 km) W from epicenter |
Watsonville California, The United States. |
IV
Light |
8 mi (13 km) NE from epicenter |
Gilroy California, The United States. |
IV
Light |
9 mi (15 km) S from epicenter |
Prunedale California, The United States. |
IV
Light |
14 mi (23 km) ESE from epicenter |
Hollister California, The United States. |
IV
Light |
15 mi (24 km) N from epicenter |
Morgan Hill California, The United States. |
III
Weak |
16 mi (26 km) S from epicenter |
Salinas California, The United States. |
III
Weak |
18 mi (29 km) SSW from epicenter |
Marina California, The United States. |
III
Weak |
19 mi (30 km) WNW from epicenter |
Live Oak California, The United States. |
III
Weak |
21 mi (34 km) W from epicenter |
Santa Cruz California, The United States. |
III
Weak |
24 mi (38 km) SSW from epicenter |
Seaside California, The United States. |
III
Weak |
25 mi (40 km) SW from epicenter |
Pacific Grove California, The United States. |
III
Weak |
25 mi (41 km) SSW from epicenter |
Monterey California, The United States. |
III
Weak |
28 mi (45 km) NW from epicenter |
Los Gatos California, The United States. |
III
Weak |
30 mi (49 km) NNW from epicenter |
Campbell California, The United States. |
III
Weak |
32 mi (51 km) NW from epicenter |
Saratoga California, The United States. |
II
Weak |
32 mi (52 km) NNW from epicenter |
San Jose California, The United States. |
III
Weak |
33 mi (53 km) NNW from epicenter |
Alum Rock California, The United States. |
II
Weak |
35 mi (56 km) NNW from epicenter |
Santa Clara California, The United States. |
III
Weak |
35 mi (57 km) NW from epicenter |
Cupertino California, The United States. |
II
Weak |
38 mi (61 km) NW from epicenter |
Sunnyvale California, The United States. |
III
Weak |
39 mi (62 km) NNW from epicenter |
Milpitas California, The United States. |
II
Weak |
39 mi (62 km) SSE from epicenter |
Soledad California, The United States. |
III
Weak |
40 mi (65 km) NW from epicenter |
Mountain View California, The United States. |
II
Weak |
42 mi (67 km) NW from epicenter |
Los Altos California, The United States. |
II
Weak |
45 mi (73 km) NW from epicenter |
Palo Alto California, The United States. |
II
Weak |
45 mi (73 km) ENE from epicenter |
Los Banos California, The United States. |
II
Weak |
47 mi (76 km) NW from epicenter |
East Palo Alto California, The United States. |
II
Weak |
47 mi (76 km) NW from epicenter |
Menlo Park California, The United States. |
II
Weak |
48 mi (77 km) NNW from epicenter |
Newark California, The United States. |
II
Weak |
48 mi (77 km) NNW from epicenter |
Fremont California, The United States. |
II
Weak |
48 mi (78 km) NE from epicenter |
Patterson California, The United States. |
II
Weak |
51 mi (82 km) NW from epicenter |
Redwood City California, The United States. |
III
Weak |
52 mi (83 km) NNW from epicenter |
Union City California, The United States. |
II
Weak |
53 mi (85 km) NW from epicenter |
San Carlos California, The United States. |
II
Weak |
53 mi (86 km) N from epicenter |
Livermore California, The United States. |
II
Weak |
53 mi (86 km) NNW from epicenter |
Pleasanton California, The United States. |
II
Weak |
54 mi (87 km) NW from epicenter |
Belmont California, The United States. |
II
Weak |
56 mi (90 km) NW from epicenter |
Foster City California, The United States. |
III
Weak |
57 mi (91 km) NNW from epicenter |
Dublin California, The United States. |
II
Weak |
57 mi (92 km) NNW from epicenter |
Hayward California, The United States. |
II
Weak |
58 mi (94 km) NNE from epicenter |
Tracy California, The United States. |
II
Weak |
58 mi (94 km) NW from epicenter |
San Mateo California, The United States. |
II
Weak |
59 mi (95 km) NNW from epicenter |
Castro Valley California, The United States. |
II
Weak |
60 mi (96 km) NE from epicenter |
Turlock California, The United States. |
II
Weak |
61 mi (98 km) NE from epicenter |
Ceres California, The United States. |
II
Weak |
62 mi (100 km) NE from epicenter |
Modesto California, The United States. |
II
Weak |
70 mi (113 km) NNW from epicenter |
Oakland California, The United States. |
II
Weak |
73 mi (117 km) NW from epicenter |
San Francisco California, The United States. |
III
Weak |
75 mi (121 km) NNE from epicenter |
Stockton California, The United States. |
II
Weak |
104 mi (168 km) E from epicenter |
Fresno California, The United States. |
I
Not felt |
116 mi (186 km) N from epicenter |
Sacramento California, The United States. |
I
Not felt |
186 mi (300 km) NNE from epicenter |
Carson City Nevada, The United States. |
Earthquake Intensity Map
The maximum intensity (MMI Scale) caused by this earthquake is V. The map below shows in which areas this earthquake was the most and least impactful. It is based on data from the US Geographic Survey.
Aftershocks detected
Since this main shock, 1 smaller aftershock was detected. A 2.5 magnitude earthquake hit 3 days later 21 mi (33 km) east of this earthquake.
Before this earthquake struck, 1 smaller foreshock occurred. A 2.7 magnitude earthquake hit 3 days earlier nearby.
Overview of foreshocks and aftershocks
Classification | Magnitude | When | Where |
---|---|---|---|
Foreshock | M 2.7 |
3 days earlier Sep 26, 2024 10:37AM (Los Angeles Time) | 16 mi (26 km) ESE from Main Shock. |
Main Shock This Earthquake |
M 4.2 |
Sep 29, 2024 02:47AM (Los Angeles Time) | - |
Aftershock | M 2.5 |
3 days later Oct 1, 2024 09:47PM (Los Angeles Time) | 21 mi (33 km) E from Main Shock. |
More earthquakes coming?
Aftershocks are usually at least 1 order of magnitude less strong than main shocks. The more time passes, the smaller the chance and likely strength of any potential aftershocks.
It's always adviced to be cautious of the risk of a larger shock following any significant earthquake, however this risk is fairly small. There is a roughly 94 percent change that no larger main shock will follow in the days following this earthquake.
Read: How to Stay Safe during an Earthquake (cdc.gov).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 September 7th, 2024, when a 4.3 magnitude earthquake hit 142 mi (229 km) further north-northwest. An even stronger magnitude 6 earthquake struck on July 8th, 2021.
In total, 47 earthquakes with a magnitude of 4.2 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 3 months.
Sources
Last updated 09/10/24 00:18 (). This article is automatically generated based on available data. We keep checking multiple sources for additional information. This article gets updated as new details on this earthquake become available.