A magnitude 3.6 earthquake was felt in Los Angeles on Monday night, particularly on the Westside and in the San Fernando Valley.

The epicenter of the earthquake, which struck at 11:20 p.m., was just west of the Sepulveda Pass of the 405 Freeway in the Santa Monica Mountains.

The U.S. Geological Survey’s ShakeMap said light to moderate shaking — categorized as intensity 4 and 5, and depicted on a map as aqua and green — was felt in parts of the Westside and the San Fernando Valley, but probably was not heavy enough to cause any significant damage. Shaking was also felt in Los Feliz, Silver Lake and Glendale.

But not everyone felt the temblor — some in Westwood slept through the earthquake.


“We get these size earthquakes fairly frequently,” said U.S. Geological Survey seismologist Zachary Reeves. “Any severe damage would be pretty unlikely.”

Moderate shaking — or intensity 5 shaking — is defined by the USGS as “felt by nearly everyone; many awakened. Some dishes, windows broken. Unstable objects overturned. Pendulum clocks may stop.”

Light shaking, or intensity 4 shaking, is defined as having a strength that can awaken some people and disturb dishes, windows and doors; can cause walls to make a cracking sound; or provide the sensation of a heavy truck striking a building.

There were no reports of damage. It was followed by a 2.0 magnitude aftershock.


The last notable earthquake in the Westwood area was a 4.4 magnitude temblor that struck in 2014.

Seismologist Lucy Jones said on Twitter that the quake was on a small east-trending thrust fault.

This graphic shows how the quake was felt and reported:

People lauch LastQuake app within sec of ground shaking: Eyewitnenesses are real time sensors pic.twitter.com/fSWcQIv8A9 — EMSC (@LastQuake) September 19, 2017


(USGS)

Did you feel it? Report what you felt to the @USGS DYFI? web app: https://t.co/cgiISfBUx7 https://t.co/ZmOgGZA9Bc — SCEC (@SCEC) September 19, 2017

Quite the jolt on the westside of LA! #earthquake #LAquake — Daniel Swain (@Weather_West) September 19, 2017

Woah! Pretty strong earthquake. Felt a rumble and then a quick boom. #earthquake — Carlos Granda (@abc7carlos) September 19, 2017


Of course there's an earthquake on my birthday. — billy eichner (@billyeichner) September 19, 2017

My favorite Twitter is was-that-an-earthquake Twitter. Yes, I also just checked here first. — Amy Nicholson (@TheAmyNicholson) September 19, 2017

We had a strong jolt, then rolling. Biggest one felt here in a couple of years, at least. Santa Monica. — John Arthur (@jarthur47) September 19, 2017

Westwood quake on an east-trending thrust fault. Too small to assign to a mapped fault. — Dr. Lucy Jones (@DrLucyJones) September 19, 2017


Westwood M3.6 was felt by so many people because so many people live nearby. We didn't feel a thing in Pasadena. — Dr. Lucy Jones (@DrLucyJones) September 19, 2017

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UPDATES:

Noon: Updated with more graphics.

9:30 a.m.: Updated with information on fault.


7:35 a.m. Tuesday: Updated with reference to a 2104 quake in the Westwood area, and an aftershock.

This post was originally published at 11:55 p.m. Monday