Shallow M4.2 Earthquake hit near Watsonville in The United States on Sunday Night.

Written by Earthquakelist.org on September 29th, 2024. Last updated October 22nd, 2024.

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.

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.
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

DISCLAIMER: We strongly suggest to closely monitor advice from local authorities with regards to tsunami risks. Our analysis is based on automatically collected data from external sources, and these might contain mistakes. In addition, earthquakes can cause landslides that may lead to a tsunami, or be a followed by another, potentially stonger, earthquake.

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 3,270 people. At V, it is the highest MMI level this earthquake has caused. The majority of people (roughly 5.4 million) live in an area exposed to level I, where not noticeable and no damage is expected.

People	MMI Level	Shaking	Damage
5,440,000	I	Not noticable	None
4,982,000	II	Very weak	None
3,655,000	III	Weak	Probably none
167,100	IV	Light	Likely none
3,270	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

Cities and Towns around the epicenter of this earthquake.
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.

I Not felt

II Weak

III Weak

IV Light

V Moderate

VI Strong

VII Very Strong

VIII Severe

IX Violent

X Extreme

Earthquake Intensity Map based on Shakemap Data provided by USGS.

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

Detected MAG2.5+ earthquakes within within 100km (62 mi), that occurred in the three days before and after the main shock.
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 22/10/24 01:28 (). 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.