MONITORING AND FORECAST MEGA-EARTHQUAKE IN CALIFORNIA, Мs≥7.8         /May 09, 2011/

  In messages from May 11, 2009 and May 12, 2009 the forecast of strong earthquake in Southern California on the basis of SS California with threshold magnitude of Mp=7.5 has been given. There it was predicted that in southern California earthquake with М=7.7-7.9 with 2014 for 2016 on a segment of San Andreas Fault (from Palmdale through San Bernardino to Riverside) can be prepared. In the message from October 4, 2009 the possible scenario of preparation of earthquake with М=7.8 in 2011 on a segment of San Andreas Fault from Parkfilda (Cholame Valley) to Wrightwood has been considered.

I. MEGA SS California, Мs≥7.8.  After catastrophic earthquake in Japan we have considered mega-earthquake possibility in SS California with magnitude М≥7.8. Mega SS California treats the category of badly defined. There were three earthquakes 1690, 1857 and 1906. At earthquake of 1690 rupture has occurred from San Bernardino through Coachella Valley to Salton Sea. From three strong earthquakes we can restore two come to the end seismic cycles for earthquake the Fort Tijon 1857, М=7.9 and San Francisco 1906, М=7.8 (see Fig.1 and Tab.1). The average period of repeatability makes 108 years. After last earthquake of 1906 has passed 105 years. The following on repeatability should occur in 2014. On two come to the end seismic cycles using values of Tab.1 we will define the law of seismic entropy production (see Fig.2):
                                                                                                                  Ks=0.312W+10.780                            (1)

For May 2011 in mega system entropy W=19.768. Substituting in the formula (1) we will define a power class of expected earthquake Ks=16.947 that corresponds to magnitude М=8.1. Today in southern California is prepared earthquake with energy in 1.8 times more than  at earthquake of 1857. Rupture on a San Andreas Fault at earthquake 1857 was stretched to 300 km, from Parkfilda (Cholame Valley) to Wrightwood; horizontal displacement reached to 9 meters. At expected earthquake with М=8.1 if all energy is dated for San Andreas Fault that rupture on a fault will reach 520 km, and the area of a rupture plane 10400 км², at an average slip of 5 m. I.e. will make the sum of ruptures of 1690 and 1857 earthquakes (see Fig.1). In Fig.3 the track diagram Mega SS California is resulted. From the track diagram it is visible that earthquake-indicator Kern Caunty 1952 has occurred near to instability area mega earthquakes. This earthquake has essentially strengthened SS and has withdrawn a track from attractor (a yellow line in a Fig.3). To second half 80th years the track has again come nearer to attractor, but the subsequent strong earthquake-indicators 1989, 1992 and 1999 have removed again a track from attractor. As the system is badly defined, we have calculated attractor on points of earthquake-indicators 1952 and 1992 (in general it is incorrect):

K=0.740W+2.422                     1952-1992       (2)

For May 2011 K=17.078. Substituting in (2) we will find critical value of entropy Wk=19.800. At seismic calm entropy will reach this size by February, 2014. So, on a cycle of repeatability and critical value of entropy earthquake with М=8.1 should occur till March 2014 in zone ВС a Fig. 1.

 

	Date	Fi	La	K	W	Ks	Ms	Pк	Pw	P	Name
0	1690	-	-	16.300?	18.620?	16.7	7.8	-	-	-	Salton trough
1	1857.01.09	35.30	119.30	16.377	18.963	17.0	7.9	45.05%	22.25%	9.9%	Fort Tijon
2	1906.04.18	37.42	122.50	16.356	18.642	16.7	7.8	50.40%	52.37%	26.4%	San Francisco
3	2011.05.08			17.078	19.768	16.9	8.1	99.50%	96.30%	95.8%	Southern Califor.

Fig.3. The track diagram Mega SS California. Earthquakes 1952, 1989, 1992 and 1999 have rejected a track from attractor (a yellow lines). In 2011-2014 track will be in a zone of instability of Southern California.

Fig.5. Fragments of track diagrams Mega SS California and the Central Kuriles on one plane. Earthquakes 1952 and 1951 have removed tracks from attractors according to California and Kuriles (straight lines).

Fig.4. SS Central Kuriles M≥7.8. The map is turned clockwise on 90º. The seismic source 2006, М=8.1 is shown. A red line-bottom border of displacement on a plane of subduction.

Fig.2. The energy diagram Mega SS California. Catastrophic earthquake М=8.1 is prepared. The hypothetical place of earthquake 1690 is shown.

Fig.1. Mega SS California. Are shown area of sources three strong earthquakes. In zone ВС there is a preparation of catastrophic earthquake М=8.1. 

II. THE COMPARATIVE ANALYSIS AND THE FORECAST. Mega SS Central Kuriles and California
As Mega SS California is badly defined, we have carried out the comparative analysis of preparation mega earthquakes in California with other systems. From all found us SS close values had tracks of preparations of three earthquakes in subduction zones of Japan and Kuriles. From them the closest values the track of preparation of earthquake on November 15, 2006, М=8.1 had in SS Central Kuriles. In Fig.4 the source of this earthquake and contours SS Central Kuriles on a map turned clockwise on 90º is shown. Time of preparation of this earthquake 91 years. Slips from 1 to 9 m (average of 2.5 m to depths of 30 km) occurred on a subduction plane area 250х100 км²=25000 км². In Fig.5 the fragment of a track of this earthquake combined with a track of preparation of catastrophic earthquake in Southern California is shown. As well as earthquake of 1952 in case of California earthquake-indicator of 1951 with М=7.4 was essentially rejected by a track from attractor and only by 2006 it has again come nearer to instability area.
The comparative analysis shows that despite a different plate tectonics situations in Southern California and Kuriles the developed dynamic situation in Southern California is comparable with subduction zone of central Kuriles. Unlike preparations of earthquakes 1857 and 1906 system enormous efforts not only for transform motions, but also for dipping/thrust processes are required. Earthquake of 2006 in Kuriles has occurred at W=19.766 K=17.053. Coordinates of track in case of California on May 2011 have already surpassed these values, but critical value of entropy is inconvenient for estimating. Attractor for Kuriles on points 1951 and 2006 looks like: K=0.697W+3.269. If to take it basis for track of California the track will reach critical value of entropy Wk=19.802 by August, 2014, and the hypothetical source of expected earthquake in Southern California would have an appearance resulted in Fig.6.
As, unlike Kuriles, in California average horizontal displacement will be more, presumably, twice (5m) the total area of motions will be twice less, an order 12000 км².
In a reality with the account fault structures, the situation will be an average between described in point I and II. The total length of a faultings to be distributed between a San Andreas Fault (70 %) and other Faults (Sierra Madre of 13 %, San Jacinto of 9 %, San Gorgonio of 4 %...). It can be occurred in the form of the cascade of several strong aftershocks in narrow time interval. In Fig.7 the expected zone of a seismic source with М=8.1 is resulted. Earthquake can occur at any time, final date first half of 2014. The forecast of this mega-earthquake removes/replaces the previous forecasts made for SS California with М≥7.5 (see the message beginning). There is in force that earthquake in Parkfilde can serve as the trigger of expected accident.

Fig.7. Predicted source area mega earthquakes with М=8.1 taking into account the source of Kuril earthquake and fault structures of Southern California.

Fig.6. Hypothetical source area of preparation subduction mega earthquakes in Southern California (imposing source area of Kuril earthquake 2006).