Pacific Summary. 18 September 2017 - 23 September 2017

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Magnitude 6 risk areas are Northern Vanuatu, Guadalcanal, Central Sumatra, Southern Marianas Islands, Kamchatka Peninsula, Colima, Guerrero. Oaxaca, El Salvador, Costa Rica, Barbuda, South of Titicaca, North of Valparaiso, Inland Valparaiso.
Volcanic activity may increase.
Ambae, Agung, Sinabung, Sakurajima, Suwanosejima, Shiveluch, Bogoslof, Reventador.
Volcanoes may dominate quakes.
The period is likely to be extended.

Update. 18 September 11.30pm
18 September.
New Britain 5.7 2.26am
South Atlantic Ocean 5.7 5.28pm
Eruption Sinabung, Sakurajima.
Steady mild solar conditions drove some quake activity.
Sinabung let off 3 mild eruptions. A bigger eruption is possible on 19 September.
Sakurajima is erupting easy forecast pick.
Bismarck Sea, Peru/Ecuador Border, Pangai are added to Mag 6 risk locations on 19 September.
Note. Bismarck Sea is a different location to the 5.26pm New Britain 5.7, the biggest Pacific quake on 18 September.
Mag 6 risk location Barbuda is near to Hurricane Maria...there is a link between quakes and weather.
Quakes are likely to be isolated.
Volcanic data is usually slow coming in and may be incomplete for 18 September.
Volcanoes seem likely to be active on 19 September.
Sinabung is higher risk.

Update. 19 September 11.00pm
19 September.
North of Valparaiso 5.8 1.46am
Eruption Sakurajima.
Quakes were generally subdued.
Biggest quake gave excellent location success.
Volcanoes were quieter than expected.
Agung is hot and could erupt anytime.
No data for other volcanoes. Data may come later.
Hurricane Maria briefly powered up to Cat 5 as it crossed onto warmer Caribbean water and was slightly powered up by mild, steady solar conditions.
Maria could cause a lot of misery. Some islands are set to be hit twice following major destruction by Hurricane Irma last week.
Spectacular aurorae have been sighted in the Northern Hemisphere several days running.
Isolated Pacific quakes are possible on 20 September, the forecast period is closing.
Volcanoes may still be active...the forecast was for volcanoes to dominate.

Update. 20 September 8.30am
20 September.
Puebla, Mexico 7.1 6.14am
Eruption Kliuchevskoi.
The big Puebla 7.1 has hit near Mexico City and there are reports of major damage.
Puebla State is adjacent to risk locations Guerrero and Oaxaca.
Popocateptl, overlooking Mexico City is added to volcano risk.
Kuril Islands, Molucca Sea, Baja California, Southern California are added to Mag 6 risk locations.
Solar quake driving conditions held strong overnight but are likely to steadily weaken today.
The forecast period may be extended.
The presence of big quakes and hurricanes in the same areas for the second time in two weeks (see 8 September forecast) isn't coincidental.
There is a link between quakes and weather...auroras make no distinction.
Hurricane Maria is still very powered up at Cat 4/5 and has caused much damage.

Update. 21 September 2.00am
20 September.
250 km west of Auckland Island 6.1 1.43pm
Eruption Karymsky.
The Mexico 8.1 was on the forecast radar but the Auckland Island 6.1 wasn't.
The Mexico 8.1 is an unfolding tragedy...hundreds dead and dozens of buildings collapsed in Mexico City and Puebla.
Volcanoes are still relatively quiet but tend to become active near the end of or soon after a quake period.
Solar quake driving conditions were strong overnight but steadily weakened during the day.
Solar conditions are still above the threshold for driving quakes on 21 September.
Late isolated quake activity is possible as the period closes.
Volcanoes could be active 21 September.

Update. 22 September 12.00am
21 September.
Eastern Honshu 6.1 4.37am
Vanuatu/Erromango 6.4 8.09am
Bismarck Sea 5.9 10.13am
The forecast outlook for volcanoes to dominate quakes is a mistake.
The biggest quake period since the 22 January Bougainville 7.9 has unfolded.
Solar conditions steadily weakened on 21 September, quakes came early in the day.
Solar conditions are almost below the threshold for quakes to occur.
The forecast period is extended, quakes are likely to be infrequent or absent on 22 September as the period closes.

18 September.
New Britain 5.7 2.26am
South Atlantic Ocean 5.7 5.28pm
Eruption Sinabung, Sakurajima.
19 September.
North of Valparaiso 5.8 1.46am
Eruption Sakurajima.
20 September.
Puebla, Mexico 7.1 6.14am
250 km west of Auckland Island 6.1 1.43pm
Eruption Karymsky, Kliuchevskoi.
21 September.
Eastern Honshu 6.1 4.37am
Vanuatu/Erromango 6.4 8.09am
Bismarck Sea 5.9 10.13am
22 September.
Gulf of California 5.5 5.33pm
23 September.
Offshore Northern California 5.7 7.50pm
Eruption Sinabung, Ambae, Karymsky.
The biggest quake period since the six month Mag 7 Pacific quake spell ended suddenly with the 22 January Bougainville 7.9 gives credit to the outlook for September and October to be active months.
The forecast significantly chased a second big Mexico quake in two weeks.
The period began with moderate quakes on 18-19 September before the big 20 September Mexico 7.1 flattened many builidings in Mexico City and Puebla and took over 200 lives.
Building standards must be low because the quake was 100km from Mexico City.
Strong solar conditions continued for two days...quakes followed.
The 20 September Auckland Island 6.1 was near the 11 July Auckland Island 6.6.
The quake was followed by the Cook Strait 5.0 just an hour later, prompting much online discussion about whether the quakes were linked and even if the Mexico 7.1 was linked.
Seismologists, lacking any understanding of the magnetic origin of quakes, responded negatively leaving many people wondering.
The addition of Bismarck Sea was justified on 21 September.
The addition of Baja California was justified. Solar conditions were easing on 22 September, the Gulf of California 5.5 was the biggest Pacific quake and good location success.
Note. Baja California risk location was added to the written update but cleverly omitted from the map. The location is added to the summary map.
The 23 September Offshore Northern California 5.7 wasn't a risk location but two big quakes at either end of California could be significant.
The period was forecasted to be volcanic and was to some extent.
Bali volcano Agung is being evacuated and ready to blow.
Volcanic pressure is building in Indonesia and Vanuatu.
A new period due early 25 September could see some eruptions in Bali and Vanuatu.
Southern Hemisphere could be higher risk for quakes.
Strong solar conditions during the period kept Hurricane Maria powered up to Cat 4 as it crossed onto Puerto Rico with severe damage.

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