Skip to content

Post ShakeAlert Message Summaries


Post ShakeAlert Message Summaries provide information about earthquakes detected by the ShakeAlert Earthquake Early Warning System and ShakeAlert’s performance during these events. They summarize how accurately the ShakeAlert System estimated the earthquake’s location and magnitude, how many seismic stations contributed data to these estimates, and how much warning time nearby cities may have received. These summaries are automatically generated for all USGS-issued ShakeAlert Messages with an estimated peak magnitude (M) of 3.5 or larger. Only at M 4.0 or larger are ShakeAlert Messages human-reviewed and forwarded to the National Earthquake Information Center to be posted at www.earthquake.usgs.gov. Summaries for earthquakes less than M 4.0 provide our scientists with more frequent tests of software readiness, but their results are generally not reviewed for quality or accuracy.

Please Note: USGS does not warrant that this information resource will be available without interruption, be error-free, or that any errors must be corrected. Post ShakeAlert Message Summaries are provided “AS IS” and without any warranty, express, implied, or otherwise, regarding its accuracy or performance. Any reliance upon this resource is at the express and sole risk of the user, including its employees, assigns, and insurers.

FileDate PostedSize
1965_post_event_summary.pdf
February 02, 2022 330.01 KB
1963_post_event_summary.pdf
January 22, 2022 277.76 KB
1962_post_event_summary.pdf
January 22, 2022 303.57 KB
1961_post_event_summary.pdf
January 18, 2022 351.52 KB
1960_post_event_summary.pdf
January 17, 2022 313.64 KB
1959_post_event_summary.pdf
January 13, 2022 348.84 KB
1958_post_event_summary.pdf
January 08, 2022 319.17 KB
1957_post_event_summary.pdf
January 06, 2022 176.93 KB
1956_post_event_summary.pdf
January 06, 2022 280.64 KB
1955_post_event_summary.pdf
January 03, 2022 315.32 KB
1954_post_event_summary.pdf
January 01, 2022 288.41 KB
1953_post_event_summary.pdf
December 31, 2021 241.65 KB
1820_2021-06-12_044137_9_4_mi_NW_of_Calipatria_3_6.pdf
December 30, 2021 298.60 KB
1952_post_event_summary.pdf
December 30, 2021 114.89 KB
1951_post_event_summary.pdf
December 28, 2021 107.26 KB
1944_2021-12-24_14:24:25_33.6_mi_W_of_Rio_Dell_3.6.pdf
December 27, 2021 163.11 KB
1950_post_event_summary.pdf
December 26, 2021 151.50 KB
1949_post_event_summary.pdf
December 26, 2021 318.13 KB
1947_post_event_summary.pdf
December 25, 2021 105.73 KB
1948_post_event_summary.pdf
December 25, 2021 129.99 KB
1946_post_event_summary.pdf
December 25, 2021 140.12 KB
1945_post_event_summary.pdf
December 24, 2021 142.14 KB
1943_post_event_summary.pdf
December 24, 2021 105.48 KB
1942_post_event_summary.pdf
December 23, 2021 106.56 KB
1941_post_event_summary.pdf
December 23, 2021 240.38 KB
1940_post_event_summary.pdf
December 21, 2021 118.23 KB
1939_post_event_summary.pdf
December 21, 2021 171.19 KB
1935_2021-12-20_21:52:53_13.7_mi_W_of_Rio_Dell_3.5.pdf
December 21, 2021 218.84 KB
1938_post_event_summary.pdf
December 21, 2021 135.36 KB
1937_post_event_summary.pdf
December 21, 2021 248.74 KB
1936_post_event_summary.pdf
December 20, 2021 247.41 KB
1934_post_event_summary.pdf
December 20, 2021 228.52 KB
1933_post_event_summary.pdf
December 20, 2021 181.30 KB
1932_post_event_summary.pdf
December 17, 2021 322.13 KB
1920_2021-10-25_23:42:35_31.8_mi_S_of_King_City_4.7.pdf
December 15, 2021 277.13 KB
1931_post_event_summary.pdf
December 14, 2021 181.54 KB
1930_post_event_summary.pdf
December 08, 2021 381.51 KB
1929_2021-12-04_09:27:32_10.6_mi_E_of_Mexicali_B.C._3.1.pdf
December 07, 2021 276.79 KB
1929_2021-12-04_092722_11_1_mi_E_of_Mexicali_B_C__1_9.pdf
December 04, 2021 271.18 KB
1928_post_event_summary.pdf
December 04, 2021 273.87 KB
1928_2021-12-04_092001_10_9_mi_E_of_Mexicali_B_C__3_5.pdf
December 04, 2021 275.97 KB
1924_2021-11-04_00:24:34_33.9_mi_N_of_Willits_3.9.pdf
December 03, 2021 303.21 KB
1927_2021-11-27_073526_69_1_mi_W_of_Trinidad_3_8.pdf
November 27, 2021 114.40 KB
1926_2021-11-17_194343_1_0_mi_NE_of_San_Ramon_4_0.pdf
November 17, 2021 400.46 KB
1925_2021-11-11_150505_10_6_mi_SW_of_Clearlake_3_3.pdf
November 11, 2021 306.27 KB
1924_2021-11-04_002434_33_9_mi_N_of_Willits_3_9.pdf
November 04, 2021 300.14 KB
1923_2021-11-03_002451_10_7_mi_SW_of_Rio_Dell_4_2.pdf
November 03, 2021 241.79 KB
1922_post_event_summary.pdf
November 02, 2021 277.94 KB
1921_post_event_summary.pdf
October 30, 2021 103.37 KB
1920_2021-10-25_234235_31_8_mi_S_of_King_City_4_7.pdf
October 26, 2021 276.59 KB