5.5, 252km W of Ferndale, California

Disclaimer: This information is intended solely for research and should not be used for communications with the media or the public.

Table Of Contents

• Mainshock Details
  • USGS Products
  • Nearby Faults
• Sequence Details
  • Magnitude Vs. Time Plot
  • Aftershock Locations
  • Cumulative Number Plot
  • Magnitude-Number Distributions (MNDs)
• Significant Foreshocks
  • M4.7 0 days before

Mainshock Details

(top)

Information and plots in the section are taken from the USGS event page, accessed through ComCat.

Field	Value
Magnitude	5.5 (mww)
Time (UTC)	Mon, 18 May 2020 07:02:34 UTC
Time (UTC)	Mon, 18 May 2020 07:02:34 UTC
Location	40.8281, -127.2301
Depth	10.0 km
Status	reviewed

USGS Products

(top)

ShakeMap	Did You Feel It?	PAGER

Nearby Faults

(top)

No UCERF3 fault sections are within 10km of this event's hypocenter.

Sequence Details

(top)

These plots show the aftershock sequence, using data sourced from ComCat. They were last updated at 2020/05/29 20:47:06 UTC, 11.57 days after the mainshock.

3 M≥0 earthquakes within 10 km of the mainshock's epicenter.

	First Hour	First Day	First Week	To Date
M 0	0	0	3	3
M 1	0	0	3	3
M 2	0	0	3	3
M 3	0	0	3	3
M 4	0	0	1	1

Magnitude Vs. Time Plot

(top)

This plot shows the magnitude vs. time evolution of the sequence. The mainshock is ploted as a brown circle, foreshocks are plotted as magenta circles, and aftershocks are plotted as cyan circles.

First Week	To Date

Aftershock Locations

(top)

Map view of the aftershock sequence, plotted as cyan circles. The mainshock and foreshocks are plotted below in brown and magenta circles respectively, but may be obscured by aftershocks. Nearby UCERF3 fault traces are plotted in gray lines, and the region used to fetch aftershock data in a dashed dark gray line.

First Day	First Week	To Date

Cumulative Number Plot

(top)

This plot shows the cumulative number of M≥0 aftershocks as a function of time since the mainshock.

Magnitude-Number Distributions (MNDs)

(top)

These plot shows the magnitude-number distribution of the aftershock sequence thus far. The left plot gives an incremental distribution (the count in each magnitude bin), and the right plot a cumulative distribution (the count in or above each magnitude bin).

Incremental MND	Cumulative MND

Significant Foreshocks

(top)

Foreshock(s) with M≥6 or with M≥M_Mainshock-1.

M4.7 0 days before

(top)

Information and plots in the section are taken from the USGS event page, accessed through ComCat.

Field	Value
Magnitude	4.7 (mb)
Time (UTC)	Mon, 18 May 2020 07:02:34 UTC
Time (UTC)	Mon, 18 May 2020 07:02:34 UTC
Location	40.7836, -127.2776
Depth	10.0 km
Status	reviewed

USGS Products

(top)

Did You Feel It?

Nearby Faults

(top)

No UCERF3 fault sections are within 10km of this event's hypocenter.