Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Global tsunami distribution

Global tsunami cause Historical tsunamis from 2000 B.C. to present frequency

(National Geophysical Data Center, NCEI, 2020)

Rapid earthquake source characterization in the context of tsunami early warning 1 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Tsunami early warning systems

DECISION MATRICES that rely on:  Latitude  Longitude  Depth  Magnitude

Rapid earthquake source characterization in the context of tsunami early warning 2 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Objectives

HYPOCENTER POSITION on the fault plane 3D fault geometry (STRIKE, DIP, RAKE)

and fault length and width slip distribution

FINITE FAULT MODELS

REAL-TIME SIMULATIONS POPULATE DATABASES OF PRE-COMPUTED SCENARIOS

Rapid earthquake source characterization in the context of tsunami early warning 3 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Datasets

Finite fault models of:  Moderate to large events Mw > 6  Shallow events depth < 50 km

SRCMOD dataset USGS dataset

SRCMOD database: USGS database: http://equake-rc.info/srcmod/ https://earthquake.usgs.gov/earthquakes/search/

Rapid earthquake source characterization in the context of tsunami early warning 4 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Check and review process

 Check of the hypocentral position

 Check of the faults’ dimensions

 Check of the faults’ geometry

Rapid earthquake source characterization in the context of tsunami early warning 5 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Fault trimming

Rapid earthquake source characterization in the context of tsunami early warning 6 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Fault rotation

Rapid earthquake source characterization in the context of tsunami early warning 7 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References SRCMOD PDFs - lowest threshold

Rapid earthquake source characterization in the context of tsunami early warning 8 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References SRCMOD PDFs - highest threshold

Rapid earthquake source characterization in the context of tsunami early warning 9 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References USGS PDFs - highest threshold

Rapid earthquake source characterization in the context of tsunami early warning 10 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Fault geometry determination: first approach

SRCMOD dataset – PB2002 SRCMOD dataset – alternative zonation PB2002 is a digital model of plate boundaries provided by Bird (2003)

Rapid earthquake source characterization in the context of tsunami early warning 11 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Fault geometry determination: second approach

 Identification of the plate  Projection of the hypocenter  Computation of the border inclination  Identification of the strike angle  Attribution of dip and rake angles

Rapid earthquake source characterization in the context of tsunami early warning 12 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Japan

180° < Strike < 270°

◦ ◦ ◦ ◦ ◦ Magnitude range MS ( ) MD ( ) σD ( ) MR ( ) σR ( ) N. of events all (≥ 6) 195.98 32.76 ± 19.9 134.44 ± 83.32 150 6-6.5 192.15 31.53 ±17.77 129.76 ± 83.95 100 6.5-7 204.22 36.34 ± 24.5 150.5 ± 83.02 32 7-7.5 202.62 38.92 ± 21.21 134.08 ± 78.64 13 7.5-8.0 186.6 23.66 ±13.12 137.0 ±87.2 3 ≥ 8.0 226.5 10.5 ±0.5 110.0 ± 22.0 2 Mean values computed on all the events

◦ ◦ ◦ ◦ ◦ Magnitude range MS ( ) MD ( ) σD ( ) MR ( ) σR ( ) N. of events all (≥ 6) 200.13 29.76 ±17.06 129.27 ±79.14 135 6-6.5 197.8 29.46 ±15.6 127.73 ±78.75 93 6.5-7 207.92 30.28 ±20.57 135.92 ±81.7 25 7-7.5 201.0 35.75 ±18.88 128.67 ±79.49 12 7.5-8.0 186.66 23.66 ± 13.12 137.0 ± 87.25 3 ≥ 8.0 226.5 10.5 ± 0.5 110.0 ±22.0 2 Mean values computed on the offshore events

Rapid earthquake source characterization in the context of tsunami early warning 13 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Chile and Peru

0° < Strike < 45° or 290° < Strike < 360°

◦ ◦ ◦ ◦ ◦ Magnitude range MS ( ) MD ( ) σD ( ) MR ( ) σR ( ) N. of events all (≥ 6) 168.51 31.96 ± 20.99 125.17 ± 70.12 182 6-6.5 157.2 34.08 ± 22.2 128.2 ± 70.97 117 6.5-7 187.25 31.67 ± 20.33 124.72 ± 71.89 40 7-7.5 143.33 25.58 ± 14.75 136.16 ± 77.75 12 7.5-8.0 242.86 19.29 ± 6.27 88.0 ± 24.11 7 ≥ 8.0 227.66 20.0 ± 4.12 90.66 ± 21.44 6 Mean values computed on all the events

◦ ◦ ◦ ◦ ◦ Magnitude range MS ( ) MD ( ) σD ( ) MR ( ) σR ( ) N. of events all (≥ 6) 158.18 27.35 ± 17.86 111.89 ± 56.83 148 6-6.5 144.01 28.38 ± 18.62 111.79 ± 55.88 92 6.5-7 176.28 28.64 ± 18.82 111.86 ± 57.34 36 7-7.5 132.75 23.0 ± 11.93 142.88 ± 82.54 8 7.5-8.0 231.33 17.0 ± 3.05 93.5 ± 21.6 6 ≥ 8.0 227.67 20.0 ± 4.12 90.67 ± 21.43 6 Mean values computed on the offshore events

Rapid earthquake source characterization in the context of tsunami early warning 14 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References General workflow

Latitude SEISMIC Longitude Proposed NETWORK Depth algorithm Magnitude

TSUNAMI SIMULATIONS Slip distribution 3D Fault Geometry

 strike, dip and rake angles  fault length and width  selection of one or multiple scenarios on the basis of FORECASTING the hypocenter location on the fault  2D Gaussian slip distribution as an approximation for on-fault slip heterogeneity

Rapid earthquake source characterization in the context of tsunami early warning 15 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References The 2015 Illapel earthquake, Chile

Latitude -31.59° N Longitude -71.67° E Depth 29 km Magnitude 8.23

Strike (◦) Dip (◦) Rake (◦) Length (km) Width (km) SRCMOD 6.0 19.0 100.87 300.0 158.4 Algorithm 6.23 20.0 90.67 348.8 150.9

Rapid earthquake source characterization in the context of tsunami early warning 16 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Different scenarios

Rapid earthquake source characterization in the context of tsunami early warning 17 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Slip distribution (after Baglione, 2020)

Joint PDF value = 0.013 Joint PDF value = 0.012 Joint PDF value = 0.010

Rapid earthquake source characterization in the context of tsunami early warning 18 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Vertical coseismic displacements – obtained by applying Okada’s formula

Joint PDF value = 0.013 Joint PDF value = 0.012 Joint PDF value = 0.010

Rapid earthquake source characterization in the context of tsunami early warning 19 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Maximum water elevation

TSUNAMI SIMULATIONS carried out solving LINEAR SHALLOW WATER EQUATIONS through the UBO-TSUFD software developed by the Tsunami Research Team (TRT) of the University of Bologna (Tinti et al., 2013) Initial conditions:  initial vertical displacement of the sea surface is equal to the vertical displacement of the seabottom  vx ,vy =0 Boundary condition:  Full reflectivity at the coast  Full transmission at the open boundary

Rapid earthquake source characterization in the context of tsunami early warning 20 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Waveform signals

Caldera Coquimbo

Rapid earthquake source characterization in the context of tsunami early warning 21 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Waveform signals

Valparaiso Talcahuano

Rapid earthquake source characterization in the context of tsunami early warning 22 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Waveform signals

DART (Deep-ocean Assessment and Reporting of Tsunamis, https://www.ndbc.noaa. gov/dart.shtml)

Rapid earthquake source characterization in the context of tsunami early warning 23 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Aggregated results Warning state Peak coastal tsunami amplitude Action required Informative ≤ 0.3 m no action required Caution between 0.3 m and 1.0 m evacuation 80 m landward ONEMI-SHOA protocol (Catalán et al., 2020) Warning between 1.0 m and 3.0 m evacuation to a safe zone Watch ≥ 3.0 m evacuation to a safe zone

Threshold: 0.3 meters Threshold: 1 meter Threshold: 3 meters

Rapid earthquake source characterization in the context of tsunami early warning 24 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Joint PDFs for different scenarios’ subsets: THRESHOLD = 0.3 meters

20 scenarios 40 scenarios 60 scenarios

Rapid earthquake source characterization in the context of tsunami early warning 25 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Joint PDFs for different scenarios’ subsets: THRESHOLD = 0.3 meters, 60 scenarios

Rapid earthquake source characterization in the context of tsunami early warning 26 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Joint PDFs for different scenarios’ subsets: THRESHOLD = 1 meter

20 scenarios 40 scenarios 60 scenarios

Rapid earthquake source characterization in the context of tsunami early warning 27 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Joint PDFs for different scenarios’ subsets: THRESHOLD = 3 meters

20 scenarios 40 scenarios 60 scenarios

Rapid earthquake source characterization in the context of tsunami early warning 28 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Maximum water height

20 scenarios 40 scenarios 60 scenarios

Rapid earthquake source characterization in the context of tsunami early warning 29 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Conclusions

SEISMIC PROPOSED FINITE FAULT NETWORK ALGORITHM MODELS ≈ few minutes ≈ few seconds less than 5 minutes

Station name Tsunami signal arrival time TSUNAMI Coquimbo t ≈ 20 minutes FORECASTING Valparaiso t ≈ 24 minutes ≈ few minutes DART t ≈ 30 minutes Caldera t ≈ 40 minutes Talcahuano t ≈ 90 minutes

Rapid earthquake source characterization in the context of tsunami early warning 30 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Conclusions

   Rapid estimation of the fault geometry and     hypocentral position     Application:    September 16, 2015     Illapel (Chile) event   Length, width, slip distribution     from regression models    Good agreement between     data and model results      Set of finite fault models 

Rapid earthquake source characterization in the context of tsunami early warning 31 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Future developments

HYPOCENTRAL POSITION ANALYSIS:  Different trimming procedure  Zonation

FAULT GEOMETRY:  Refinement of global tessellation  Introducing check on event depth (e.g. comparison with Slab2.0)

TSUNAMI SIMULATIONS:  Adding more scenarios  Taking inundation effects into account

Rapid earthquake source characterization in the context of tsunami early warning 32 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References SRCMOD rejected event - s2016NORCIA01PIZZ fault plane

Hypocenter derived from the Data block Hypocenter provided by the Header block

Rapid earthquake source characterization in the context of tsunami early warning 33 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References USGS rejected events

Event ID Length - Width - Length - Width - data header (km) header (km) data (km) (km) 1991_p00050sq 230.0 128.0 231.12 127.51 1994_p0006qh3 210.0 150.1 210.14 148.31 1995_p000782n 196.0 216.0 197.04 214.98 1996_p0007jcu 325.0 183.3 331.36 183.42 1997_p0008btk 204.0 160.0 204.47 158.40 2001_p000ah4q 396.0 240.0 394.59 239.45 2003_p000c8kv 272.0 227.5 274.11 227.02 2003_p000cd1n 144.0 162.0 146.07 162.10 2006_p000exfn 360.0 147.0 359.80 144.67 2015_20002926 193.2 168.0 194.62 168.23 2015_20003k7a 300.0 158.4 300.22 157.26 2017_20009x42 375.0 61.6 377.07 61.66 Curved fault. USGS events with discrepancies of the order of kilometers. Event ID: 1998 p0008hzdHAYES

Rapid earthquake source characterization in the context of tsunami early warning 34 Inroduction Hypocentral position analysis Fault geometry determination General workflow and application Conclusions Appendix References Bibliography

Bird, P. (2003). “An updated digital model of plate boundaries”. In: Geochemistry, Geophysics, Geosystems 4.3. Catalán, P. et al. (2020). “Design and operational implementation of the integrated tsunami forecast and warning system in Chile (SIPAT)”. In: Coastal Engineering Journal, pp. 1–16. DOI: 10.1080/21664250.2020.1727402. NCEI (2020). DOI: 10.7289/V5PN93H7. URL: https://www.ngdc.noaa.gov/hazel/view/hazards/tsunami/runup- data?sourceMaxYear=2015&sourceMinYear=2015&sourceCountry=CHILE. Tinti, S. et al. (2013). “The UBO-TSUFD tsunami inundation model: Validation and application to a tsunami case study focused on the city of Catania, Italy”. In: Natural Hazards and Earth System Sciences 13, pp. 1795–1816. DOI: 10.5194/nhess-13-1795-2013.

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