Northern ETS Patterns

Northern (Wrangellia Zone) Slow-Slip events: 2010-2023

*The terms slow-slip events (SSE), episodic tremor & slip (ETS), and tremors are often used interchangeably.*

This page consists of screen snips from the Pacific Northwest Seismic Network’s (PNSN) Tremor Map. This page aims to allow readers to easily view Episodic Tremor & Slip events (slow-slips) side-by-side.

The slideshow, which comes first, displays three slow-slip events per page. The tremor activity is displayed in the PNSN’s “Color by Time (Jet)” option, where red is the most recent activity and blue is the oldest. This option helps illustrate how the tremor moved (migrated) from start to finish (sometimes reversing course and backtracking).

Note: A “geographic filter” was also used when compiling these images so that only the slow-slip (ETS) activity is shown on each image. This was done to (hopefully) make the slip area easier to compare from event to event.

Below are screen snips of the PNSN tremor graphs showing daily “epicenter count” activity. The dates selected below coincide with the slow-slips from the slideshow above. The dates listed in the captions are hyperlinks and will take you to the PNSN’s Tremor Map with the parameters already populated for that event. This is done, to help ensure the data is easily reproducible/verifiable for anyone interested in playing with the maps.

2010

08/07/2010 — 09/09/2010
11.282 epicenters

2011

07/22/2011 — 09/05/2011
9,157 epicenters

2012

08/29/2012 — 10/12/2012
14,371 epicenters

2013

09/06/2013 — 10/08/2013
8,865 epicenters

2014

11/02/2014 — 12/11/2014
7,669 epicenters

2015-2016

12/18/2015 — 01/17/2016
7,329 epicenters

2017: Northern events become fragmented

02/11/2017 — 03/05/2017
3,084 epicenters
03/17/2017 — 04/08/2017
7,261 epicenters

2018

05/08/2018 — 05/25/2018
2,604 epicenters
06/17/2018 — 07/16/2018
8,788 epicenters

2019

03/08/2019 — 04/16/2019
3,904 epicenters
08/10/2019 — 08/25/2019
2,690 epicenters
11/07/2019 — 11/27/2019
4,969 epicenters

2020

10/02/2020 — 11/17/2020
8,277 epicenters

2021

01/25/2021 — 02/11/2021
5,584 epicenters
09/24/2021 — 10/31/2021
7,876 epicenters

2022

03/19/2022 — 04/09/2022
5,939 epicenters
05/14/2022 — 06/07/2022
2,807 epicenters
08/02/2022 — 08/12/2022
928 epicenters

2022-2023 (as of 5/25/2023)

12/29/2022 — 01/13/2023
1,923 epicenters
04/03/2023 — 05/01/2023
9,111 epicenters
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