Marinduque earthquake swarms rising!

What's going on? A sequence of earthquakes has struck the active fault line in Marinduque including fault lines located offshore between Marinduque, Batangas and Mindoro. The record of tremors released by the Philippine Institute of Volcanology and Seismology (Phivolcs) in the area is stunning: 25 tremors during the last 8 days, 19 of which occurred during the last 3 days, but 15 of them occurring during the last 12 hours!

Aftershocks or Foreshocks?

A newspaper report, quoting Phivolcs, calls them 'aftershocks' supposedly after a magnitude 4.5 tremor struck 29 km west of Boac at 6:33 pm on October 12. As we know, aftershocks that really are smaller in intensity occur in the same area after the main shock and cannot be larger than the main shock. The problem is USGS has recorded 3 important earthquakes in the area in question occurring today as follows, none of which appear to correspond with the Phivolcs data: 

Data from USGS

Magnitude 4.5

21km WSW of Laylay, Philippines

2013-10-12 03:33:48 UTC-07:0035.0 km

Magnitude 4.7

23km W of Laylay, Philippines

2013-10-12 11:47:09 UTC-07:00104.0 km

Magnitude 4.6

19km WNW of Laylay, Philippines

2013-10-12 19:27:13 UTC-07:00117.7 km

Could these quakes actually be foreshock activities destined to occur before a major seismic event? Wiki explains that foreshock activities have been detected for about 40% of all moderate to large earthquakes and about 70% for events of M>7.0. They occur from a matter of minutes to days or even longer before the main shock. On July 24, 2013, a magnitude 4.7 earthquake also occurred in Boac, Marinduque.

Phivolcs should perhaps pay closer attention now to re-examine its data and compare them with those of other scientific institutions. In the meantime, we Marinduquenos should perhaps find time this time to pause and consider what these things could mean to those of us who love to stand and pray to God at the street corners.  

Data from Phivolcs, pay close attention, compare it with the other seismic events!

PHIVOLCS latest seismic events in the Philippines are listed below (as of Oct 13, 2013). The event parameters (hypocenter, time and magnitude) are determined using incoming data from the Philippine National Seismic Network 

Philippine Standard Time (PST)  is eight hours ahead of Coordinated Universal Time. (PST = UTC + 8H) UTC is the time standard for which the world regulates clocks and time. Earthquakes in this list with their date and time underlined in blue have reported felt intensities. Intensity ratings are based on the PHIVOLCS Earthquake Intensity Scale

Date - Time                      Latitude  Longitude   Depth   Magnitude      Location
(Philippine Time)                (ºN)         (ºE)           (km)

13 Oct 2013 - 01:13 PM        13.47     121.80        022       1.9     004 km N 66° W of Boac (Marinduque)

13 Oct 2013 - 12:50 PM        13.53     121.57        005       1.8     030 km N 74° W of Boac (Marinduque)

13 Oct 2013 - 11:14 AM        13.50     121.58        009       2.4     028 km N 78° W of Boac (Marinduque)

13 Oct 2013 - 10:27 AM        13.53     121.49        002       3.5     040 km N 77° W of Boac (Marinduque)

13 Oct 2013 - 07:20 AM        13.61     121.69        021       2.8     024 km N 42° W of Boac (Marinduque)

13 Oct 2013 - 04:41 AM        13.52     121.68        017       3.0     019 km N 65° W of Boac (Marinduque)

13 Oct 2013 - 04:28 AM        13.60     121.61        021       3.3     029 km N 57° W of Boac (Marinduque)

13 Oct 2013 - 04:12 AM        13.51     121.61        013       2.5     025 km N 76° W of Boac (Marinduque)

13 Oct 2013 - 03:57 AM        11.46     124.99        012       2.5     024 km N 4° E of Tacloban City

13 Oct 2013 - 03:16 AM        13.65     121.74        023       2.5     025 km N 26° W of Boac (Marinduque)

13 Oct 2013 - 02:46 AM        13.59     121.61        018       4.2     030 km N 58° W of Boac (Marinduque)

13 Oct 2013 - 02:40 AM        13.50     121.53        008       3.5     034 km N 81° W of Boac (Marinduque)

13 Oct 2013 - 01:58 AM        13.51     121.71        017       1.8     015 km N 63° W of Boac (Marinduque)

13 Oct 2013 - 01:44 AM        13.52     121.67        016       1.4     020 km N 67° W of Boac (Marinduque)

13 Oct 2013 - 01:08 AM        13.63     121.63        015       2.6     030 km N 48° W of Boac (Marinduque)

13 Oct 2013 - 12:55 AM        13.68     121.60        015       3.6     036 km N 45° W of Boac (Marinduque)

12 Oct 2013 - 10:54 PM        13.57     121.54        007       2.5     035 km N 67° W of Boac (Marinduque)

12 Oct 2013 - 10:05 PM        07.31     126.37        016       3.1     021 km S 84° W of Caraga (Davao Oriental)

12 Oct 2013 - 09:06 PM        13.35     121.62        001       3.0     026 km S 66° W of Boac (Marinduque)

12 Oct 2013 - 07:45 PM        05.21     126.89        050       4.0     159 km S 81° E of Sarangani (Davao Del Sur)

12 Oct 2013 - 06:59 PM        13.79     121.76        031       2.1     015 km S 18° W of Padre Burgos (Quezon)

12 Oct 2013 - 06:33 PM        13.50     121.52        006       4.5     029 km N 24° W of Boac (Marinduque)

12 Oct 2013 - 03:53 PM        17.80     120.59        027       1.8      012 km N 86° E of Cabugao (Ilocos Sur)

11 Oct 2013 - 10:45 PM        15.47     122.12        001       3.7     069 km S 63° E of Baler (Aurora)

11 Oct 2013 - 06:48 PM        17.91     120.79        024       2.9      011 km S 83° E of Nueva Era (Ilocos Norte)

11 Oct 2013 - 03:41 PM        16.41     121.14        033       1.4      004 km N 51° E of Bambang (Nueva Vizcaya)
11 Oct 2013 - 03:19 PM        13.89     121.14        020       1.8      003 km N 77° E of San Jose (Batangas)

11 Oct 2013 - 10:58 AM        13.93     120.83        041       1.4      001 km S 57° E of Calaca (Batangas)

11 Oct 2013 - 10:22 AM        13.70     120.94        019       1.6      005 km S 04° E of Mabini (Batangas)

11 Oct 2013 - 06:45 PM        18.95     121.27        015       3.5      042 km S 30° W of Calayan  (Cagayan)

10 Oct 2013 - 12:35 PM        13.91     120.44        031       2.2      023 km N 69° W of Calatagan  (Batangas)

10 Oct 2013 - 09:31 AM        06.32     124.81        036       2.5      009 km S 48° E of Surallah  (South Cotabato)

10 Oct 2013 - 12:15 AM        09.95     126.57        037       2.4      049 km N 68° E of General Luna  (Surigao del Norte)

09 Oct 2013 - 11:44 PM        12.99     120.75        008       3.3      009 km S 18° E of Santa Cruz  (Occidental Mindoro) 

09 Oct 2013 - 03:36 PM        15.19     119.63        019       2.5      040 km S 67° W of Iba  (Zambales)

09 Oct 2013 - 02:57 PM        18.15     119.74        013       4.4      083 km N 80° W of Currimao (Ilocos Norte)

09 Oct 2013 - 11:02 AM        06.71     124.13        004       2.5      010 km N 46° E of Lebak (Sultan Kudarat)

09 Oct 2013 - 04:58 AM        11.16     122.18        028       1.9      016 km S 75° E of Barbaza (Antique)

09 Oct 2013 - 04:35 AM        16.41     122.56        008       3.0      034 km S 68° E of Dinapigue (Isabela)

09 Oct 2013 - 04:11 AM        11.30     121.97        009       3.3      007 km N 77° W of Tibiao (Antique)

09 Oct 2013 - 01:05 AM        06.70     124.05        007       1.7      006 km N 19° W of Lebak (Sultan Kudarat)

08 Oct 2013 - 08:35 PM        06.27     125.81        101       2.5      015 km N 57° E of Don Marcelino (Davao del Sur)

08 Oct 2013 - 05:37 PM        06.26     126.13        043       2.9      043 km S 8° E of Governor Generoso (Davao Oriental)

08 Oct 2013 - 12:03 PM        11.30     122.02        033       2.3      011 km N 11° W of Barbaza (Antique)

08 Oct 2013 - 11:57 AM        11.26     121.98        017       3.9      009 km N 41° W of Barbaza (Antique)

08 Oct 2013 - 10:02 AM        20.36     122.20        024       4.0      027 km S 65° E of Basco (Batanes)

08 Oct 2013 - 05:48 AM        05.85     124.37        054       2.5      032 km S 60° W of Kiamba  (Sarangani)

07 Oct 2013 - 08:07 PM        06.78     126.39        016       3.0      027 km S 45° E of Mati  (Davao Oriental)

07 Oct 2013 - 07:53 PM        07.07     124.83        380       4.4      008 km S 18° E of Kabakan (North Cotabato)

07 Oct 2013 - 06:23 PM        06.64     125.34        021       2.8      015 km S 11° W of Digos City (Davao del Sur)

07 Oct 2013 - 04:53 PM        09.62     122.56        023       1.6      010 km N 47° E of Hinoba-an (Negros Occidental)

07 Oct 2013 - 01:59 PM       13.70      120.58        028       3.3      015 km S 20° W of Calatagan (Batangas)

07 Oct 2013 - 11:39 AM        06.65     123.68        034       1.5      042 km N 80° W of Kalamansig (Sultan Kudarat)

07 Oct 2013 - 01:34 AM       13.52      121.80        033       1.9      008 km N 56° W of Mogpog (Marinduque)

07 Oct 2013 - 01:18 AM       13.45      121.81        001       3.1      003 km S 88° W of Boac (Marinduque)

07 Oct 2013 - 12:17 AM       13.47      121.84        028       1.8      002 km S 79° W of Mogpog (Marinduque)

06 Oct 2013 - 11:42 PM       13.51      121.84        029       1.9      004 km N 34° W of Mogpog (Marinduque)

06 Oct 2013 - 11:38 PM       13.51      121.80        032       2.3      008 km N 31° W of Boac (Marinduque)

06 Oct 2013 - 11:36 PM       13.54      121.79        029       2.0      011 km N 29° W of Boac (Marinduque)