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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
1858_2021-08-27_123451_26_9_mi_N_of_Tehachapi_3_9.pdf
August 27, 2021 271.46 KB
1857_2021-08-27_044745_39_6_mi_SE_of_South_Lake_Tahoe_4_5.pdf
August 27, 2021 304.25 KB
1856_2021-08-23_145723_7_2_mi_N_of_Westmorland_3_7.pdf
August 23, 2021 308.11 KB
1855_2021-08-18_215022_19_9_mi_W_of_Westmorland_3_6.pdf
August 18, 2021 321.47 KB
1854_2021-08-18_214514_19_5_mi_W_of_Westmorland_3_7.pdf
August 18, 2021 323.33 KB
1853_post_event_summary.pdf
August 10, 2021 108.00 KB
1852_2021-08-07_011716_22_7_mi_SE_of_Mexicali_B_C__3_6.pdf
August 07, 2021 272.57 KB
1851_2021-08-06_143745_17_7_mi_E_of_Maricopa_3_5.pdf
August 06, 2021 338.89 KB
1850_2021-07-31_151556_12_3_mi_E_of_Cloverdale_3_4.pdf
July 31, 2021 322.47 KB
1849_post_event_summary.pdf
July 29, 2021 110.42 KB
1848_post_event_summary.pdf
July 21, 2021 107.01 KB
1847_2021-07-21_100531_17_1_mi_SW_of_Rio_Dell_4_3.pdf
July 21, 2021 229.72 KB
1846_2021-07-18_132410_44_8_mi_SE_of_South_Lake_Tahoe_3_9.pdf
July 18, 2021 332.16 KB
1845_2021-07-18_064612_24_8_mi_SW_of_Rio_Dell_5_1.pdf
July 18, 2021 207.11 KB
1844_2021-07-17_004454_39_5_mi_SE_of_South_Lake_Tahoe_3_5.pdf
July 17, 2021 320.58 KB
1843_2021-07-17_003254_40_4_mi_SE_of_South_Lake_Tahoe_3_0.pdf
July 17, 2021 327.24 KB
1842_2021-07-15_141828_39_5_mi_SE_of_South_Lake_Tahoe_4_0.pdf
July 15, 2021 324.56 KB
1841_2021-07-14_034613_38_7_mi_SE_of_South_Lake_Tahoe_4_1.pdf
July 14, 2021 319.83 KB
1840_2021-07-12_034333_47_8_mi_W_of_Fortuna_3_8.pdf
July 12, 2021 142.15 KB
1839_2021-07-09_051035_37_3_mi_SE_of_South_Lake_Tahoe_4_7.pdf
July 09, 2021 322.55 KB
1838_2021-07-09_050418_38_1_mi_SE_of_South_Lake_Tahoe_4_3.pdf
July 09, 2021 322.46 KB
1837_2021-07-09_014600_38_2_mi_SE_of_South_Lake_Tahoe_4_9.pdf
July 09, 2021 318.12 KB
1836_2021-07-09_002748_39_1_mi_SE_of_South_Lake_Tahoe_4_4.pdf
July 09, 2021 340.51 KB
1835_2021-07-09_000521_43_2_mi_SE_of_South_Lake_Tahoe_4_0.pdf
July 09, 2021 317.03 KB
1834_2021-07-08_235853_37_4_mi_SE_of_South_Lake_Tahoe_4_5.pdf
July 09, 2021 327.26 KB
1833_2021-07-08_234743_36_7_mi_SE_of_South_Lake_Tahoe_3_7.pdf
July 08, 2021 319.24 KB
1832_2021-07-08_234441_36_2_mi_SE_of_South_Lake_Tahoe_3_5.pdf
July 08, 2021 326.04 KB
1831_2021-07-08_233341_39_2_mi_SE_of_South_Lake_Tahoe_4_9.pdf
July 08, 2021 362.09 KB
1830_2021-07-08_231103_39_8_mi_SE_of_South_Lake_Tahoe_3_6.pdf
July 08, 2021 327.31 KB
1829_post_event_summary.pdf
July 08, 2021 386.39 KB
1827_2021-07-08_224948_38_7_mi_SE_of_South_Lake_Tahoe_5_9.pdf
July 08, 2021 352.24 KB
1828_post_event_summary.pdf
July 08, 2021 331.23 KB
1827_2021-07-08_224948_38_7_mi_SE_of_South_Lake_Tahoe_6_2.pdf
July 08, 2021 349.28 KB
1826_2021-07-06_023801_8_8_mi_NE_of_Ridgecrest_3_6.pdf
July 06, 2021 269.44 KB
1825_2021-07-03_232351_2_2_mi_W_of_Los_Banos_3_8.pdf
July 03, 2021 340.89 KB
1824_2021-07-03_082225_3_9_mi_NW_of_Fontana_3_5.pdf
July 03, 2021 356.71 KB
1823_2021-06-29_012948_2_2_mi_SE_of_San_Leandro_4_1.pdf
June 29, 2021 379.42 KB
1822_2021-06-23_082537_23_3_mi_SW_of_Loyalton_3_6.pdf
June 23, 2021 353.32 KB
1821_2021-06-18_082225_16_1_mi_W_of_El_Centro_3_5.pdf
June 18, 2021 293.51 KB
1819_2021-06-12_043946_9_5_mi_NW_of_Calipatria_4_3.pdf
June 14, 2021 328.43 KB
1817_2021-06-12_043028_9_5_mi_NW_of_Calipatria_3_9.pdf
June 14, 2021 313.16 KB
1816_2021-06-14_031624_10_2_mi_E_of_Cloverdale_3_5.pdf
June 14, 2021 319.42 KB
1815_2021-06-13_174313_7_0_mi_N_of_Westmorland_3_1.pdf
June 13, 2021 306.09 KB
1814_2021-06-13_065447_10_1_mi_E_of_Cloverdale_3_5.pdf
June 13, 2021 320.72 KB
1813_2021-06-12_141639_8_7_mi_NW_of_Calipatria_2_8.pdf
June 12, 2021 307.95 KB
1812_2021-06-12_111229_8_7_mi_NW_of_Shelton_3_6.pdf
June 12, 2021 332.54 KB
1811_2021-06-12_055520_10_0_mi_NW_of_Calipatria_3_6.pdf
June 12, 2021 307.50 KB
1810_2021-06-12_042734_9_5_mi_NW_of_Calipatria_3_4.pdf
June 12, 2021 310.79 KB
1809_2021-06-11_104553_5_3_mi_E_of_Watsonville_3_5.pdf
June 11, 2021 339.07 KB
1808_post_event_summary.pdf
June 07, 2021 172.87 KB