Natural Disasters: Forecasting and Nowcasting

Market Street
San Francisco
April 14, 1906
YouTube VideoJohn B Rundle
Distinguished Professor, University of California, Davis (www.ucdavis.edu)
Chairman, Open Hazards Group (www.openhazards.com)

San Francisco Earthquake
April 18, 1906 5:12 am PDT

Wreckage of City Halland the Hall of Records

Photos courtesy of the Museum of
the City of San Francisco; theSteinbrugge Collection of UC
Berkeley; and the Bancroft Library,
2UC Berkeley

The Great 1906 San Francisco
Earthquake Extended for ~ 350 kmAlong the San Andreas Fault inNorthern California.
Horizontal offsets of as much as 8
meters were observed.

Wayne Thatcher, US Geological Survey
Three coupled spatial scales visible: 1. Fault length (~430 km); 2. Slip (~m); 3. Rupture thickness (~cm)
3

Strike Slip
Faulting

Fault Zone Types
ThrustFaulting

NormalFaultingThe Earthquake ”Cycle”(Courtesy P.B. Rundle)“Strike-slip” Earthquakes (mainly horizontal motion)

Earthquakes in Nankai Trough, Japan
M Ando, Tectonophysics, v27, p112 (1975)• Data from historic writings inJapan• Basic ideas of the earthquake“cycle” essentially startedhereIdealized Model of Elastic Rebound on a Fault

Fault Stress ⌠Report of the 1906 Earthquake Investigation (1910)

Time, tFault Slip

Tt1 t2

Time, tHarry Fielding Reid (1859-1944)

Gutenberg-Richter Relation(1942)(Frequency-Magnitude Relation)

Beno Gutenberg (1889-1960)

Charles Richter (1900-1985)

Gutenberg-Richter Relation

Statistics Before and After 3/11/2011
Radius of 1000 km Around Tokyo (Accessed July 1, 2015)

Log10 (Number of EQs)

Log10 (Number of EQs)

b=1.01 +/- 0.01

MagnitudeMagnitude

All events prior to M9.1 on 3/11/2011(“Normal” statistics)

All events after M7.7 on 3/11/2011(Deficit of large events)

On Earthquake Forecasting• Why forecast? (A vocal minority of our community says weshouldn’t or can’t)– Insurance rates– Safety– Building codes• Fact: Every country in the world has an earthquake forecast(it may be an assumption of zero events, but they all haveone)• Premise: Any forecast made by the seismology community isbound to be at least as good as, and probably better than,
any forecast made by:– Politicians– Lawyers– Agency bureaucrats

Natural Time Weibull Forecast
JBR et al., Physical Review E, 86, 021106 (2012)

Data from ANSS catalog + other real time feeds

Based on “filling in” the Gutenberg-Richter magnitudefrequency relation



Example: for every ~1000 M>3 earthquakes there is 1 M>6earthquakeWeibull statistics are used to convert large-earthquake
deficit to a probability



Fully automated

Backtested and self-consistentUpdated in real time (at least nightly)

Accounts for statistical correlations of earthquake
interactions

Probability Time Series
Sendai, Japan
100 km Radius

Accessed 2016/07/06

M8.3

M>7

M9.1: 3/11/2011

M8.3: 5/24/2013

Probability Time Series
Tokyo, Japan
100 km Radius

Accessed 2016/07/06

M8.3

M>7

M9.1: 3/11/2011

M8.3 5/24/2013

Probability Time Series
Kumamoto, Japan
100 km Radius

Accessed 2016/07/06

M8.3

M>6
M7.0 2016/04/16

Probability Time Series
Kumamoto, Japan
100 km Radius

Accessed 2016/07/06

M8.3

Low probability at time ofoccurrence. Poor data ormodel problems?

M>7M7.0 2016/04/16

QuakeWorks Mobile App (iOS)(Courtesy D.E. Rundle)

NowCasting• Natural hazards tend to occur in cycles of activity– Earthquakes– El Nino Southern Oscillation (ENSO)– Pacific Decadal Oscillation (PDO)• Forecasting is a probability of future activity in thehazard cycle• Nowcasting describes the current state of the hazardcycle• The term “Nowcasting” was first used to describe thecurrent state of the economic/business cycle

ENSO: El Nino and La Nina
http://www.climate.gov

ENSO: Time Series
http://en.wikipedia.org/wiki/El_Nino

PDO

http://cses.washington.edu

PDO Time Series
http://www.nwfsc.noaa.gov

Idealized Model of the Earthquake Cycle

Cumulative Numberof Small Earthquakes
between Large
Earthquakes
Time, t• If we count the number of small earthquakes since thelast large earthquake, we expect it to increase withtime (Gutenberg-Richter relation)• So the count of small earthquakes can be viewed as amarker for the increase of stress and consequently thehazard level

Method• Select a standard-sized region, either rectangular or circle, inan area where there have been many “large” earthquakes• Consider only the “small” earthquakes MS that occur between
the “large” earthquakes ML• Define the fault system state or Earthquake Potential Score as
the cumulative probability for the number of “small”
earthquakes since the last “large” earthquake• The Gutenberg-Richter law assures that as more “small”
earthquakes occur, a “large” earthquake becomes more likely

Examples• To compare global cities, we select a standard set ofparameters• We construct a 100 km radius circle around a city of interest• For cities, we consider “large” earthquakes having ML>6• The “small” earthquakes for city hazards are determined by
the catalog completeness level:– For Global cities:

4 < MS < 6– For California cities:

3 < MS < 6

Small:Large:

4 < MS < 66 < ML

Small:Large:

4 < MS < 66 < ML

Small:Large:

4 < MS < 66 < ML

Small:Large:

4 < MS < 66 < ML

Small:Large:

4 < MS < 66 < ML

Small:Large:

4 < MS < 66 < ML

Small:Large:

4 < MS < 66 < ML

Small:Large:

4 < MS < 66 < ML

Small:Large:

4 < MS < 66 < MLSmall:
Large:

4 < MS < 66 < ML

Small:Large:

3 < MS < 66 < ML

Small:Large:

3 < MS < 66 < ML

Small:Large:

3 < MS < 66 < ML

Small:Large:

3 < MS < 66 < ML

Small:Large:

3 < MS < 66 < ML

Small:Large:

3 < MS < 66 < ML

Summary so Far• Forecasting: Computing the probability offuture activity• Nowcasting: Determining the current state ofprogress through the hazard cycle• Now: Brief discussion of Global Navigation
Satellite System Tsunami Early WarningSystem

Towards an Improved Indo-PacificTsunami Early Warning Network
John LaBrecqueNASA Science Mission Directorate
And theREADI Network TeamJapan, March 11, 2011

Banda Aceh, December 26, 2004

Global Navigation Satellite Systems (GNSS)
Can Track Tsunamis Across the Indo-PacificCurrent Tsunami Warning System
Earthquake-Magnitude-Based Tsunami Warnings(NOAA’s PTWC)

Unfortunately,
1. Earthquake magnitude is not a good indicator of a resulting tsunami;
2. DART system has inherent delays.
3. Seismic Mw estimates require at 20 minutes or moreIndo-Pacific GNSS Disaster Early Warning Network
Pacific Basin Earthquakes and Volcanic Eruptions pose regional
hazards that do not obey national boundaries.
The Pacific Basin is ringed by subduction zones and violent
volcanoes with demonstrated ability to generate large
earthquakes and devastating tsunamis that propagate basin wide.
Dense GNSS regional networks are being deployed within thecircum-Pacific and on Pacific Islands.
Communication infrastructure is available for near real time GNSS
data distribution either continuous or event responsive.

Post Processing of regional geodetic data taken on December 26,2004 Demonstrated theValue of aGlobal Regional GNSS Real Time Network
A Dense Global Real Time GPS Network would have warned of the Indian Ocean Tsunami within minutes- hours
before the seismic analysis-

GPS station displacements on 26 December, 2004 observed by the International GNSS Service
Network (IGS/GGOS). The largest arrow (SAMP) has been scaled down by a factor of two for clarity.
Ref: Blewitt, Hammond, Kreemer, Plag, Stein, Okal, 2009,J. Geodesy.

February 27, 2010: Chile M8.8 Earthquake Demonstrated First Real Time GPS
based Tsunami Prediction using GDGPSwith NASA Applied Sciences funding to The GREAT Alert Project(a): NASA's Global
Differential GPS (GDGPS)
measures the Chile M8.8
earthquake displacement
in real time at Santiago.
(b): JPL GREAT alert teampredicts a moderate sizedtsunami using the realtime GPS and the Songtsunami generation
model.
(c): NASA/CNES satellites
Jason-1 and Jason-2
confirm the tsunami
amplitude prediction ofthe GPS-based model
prediction.
Tony Song , Yoaz Bar-Sever, et al. /JPLSong Y.T., 2007, Detecting tsunami genesis and scales
directly from coastal GPS Stations, Geophys Res. Ltts.

(d): Next steps:Strengthen real time
GDPS network, automatemodels.

The 2011 Tohoku-Oki Tsunami
There are about 1,200 GPS stations (GeoNet) on JapaneseIslands. Study shows that they were capable of predicting
the tsunami and could have saved more lives if were used
(Song et al., GRL, 2012).

March 11, 2011:The GSI GEONET GPS Array•••

Demonstrated Capability to Predict a Tsunami
First use of GPS to Predict
First Observe the Resulting Tsunami

http://gps.alaska.edu/ronni/sendai2011.html: Ronni Grapenthin

The Tsunami Generated Displacement of the Ocean
Surface Couples to the IonosphereFrom Artru et al., 2005

GSI’s GEONET Also Captured the Ionospheric Coupled Waves and Imaged theTsunami Generation and Propagation-For the First Time

Ionospheric Response to Mw9.0 Tohoku Earthquake and Tsunami in Japan on March 11, 2011, A.Komjathy, D.A.Galvan, M.PHickey, P.Stephens, Mark Butala, and A.Mannucci, (http://visibleearth.nasa.gov/view.php?id=77377)