Volcanoes in north

Sheng-Rong Song Department of Geosciences, National Taiwan University Volcanic Provenance of Taiwan 120o 121o 122o E WBP N.P. N Tatun 1、Western Provenance t Kungkuan ai r Tsa olingsh an o 2、Eastern Provenance St 25 N n a Kuanhsi- w Chutung 3、Northern Provenance ai T W.P. e n a 4 、Kueishantou r r x o e e T l SRT 24 p n e i t a la m Penghu S o Pl Plate l hills C t E.P. Islands a t o s o ao a F n o a n C r n a te s T e Coastal o W Range 23

Lutao L.V Intraplate Basalts

Arc-related Lanhsu 22o Volcanics Chung et al.,, 1994 Western Provenance

福建 福建 福建 臺灣 澎湖 臺灣 西部 中部 東部 海峽 群島 西部 西北 西邊 東南 0 大 陸 地 殼

50 大陸岩石圈地函

TH

AB 100 AB AB, BA km NE,BA 軟流圈對流上拱 0 50 100km

Chung, 1990 Coastal Range of east Eastern Provenance Taiwan Eurasian Plate

TaiwanLutaoRyukyu Arc

North LanhsuLuzon Arc 80 mm/yr Hsuilanhsu South China Philippine Sea Sea Plate Hsiulanhsu

~1000-1300 BP Northern Provenance 0.29~2.1 Ma N Penghiahsu Chinshan KUANYINSHAN (Hsinchuang) VOLCANO 0 5 10 0.5~2.6Mienhuahsu Ma (km) Huapinghsu TATUN VOLCANO CHILUNG Nankan t Chilungtao GROUP aul VOLCANO Fault0.36~0.63 Ma F ~1.0 Ma GROUP ao nchi Ka LINKOU WESTERN 0.8~1.2 Ma TABLELAND FOOTHILLS TA IP EI BASIN ult Fa TAOYUAN TERRACE h HSUEHSHAN hi uc TERRANE Ch

Evolution of volcanism in northern Taiwan

Westward Advance of Western Ed ge of Subducting Philippine Plate (WEP) 3 Ma 5 Ma 2 Ma 4 Ma 1 Ma 2 Ma 1 Ma 0 100 km 0 Ma 0 Ma Opening of Okinawa Trou gh S M R 2 Ma 1 Ma 0 Ma Southward Migration of 0 Ma N55oW Ryukyu Trench 1 Ma 2 Ma Northwestward 7 cm/yr Advance of 3 Ma Manlia Trench 4 Ma 5 Ma Wang et al., 2004 Tatun Volcano Group – Active? Or Extinct? Two definitions of active volcano Empirical Definition

1. historical documented eruptions (Smithsonian Institution, 1989) 2 . A volcano is termed active if it has erupted at least once during the last 10000 or, alternatively, 5000 or 2000 years as demonstrated by any scientific method (Szakacs, 1994) 3. A set of time conditions according to volcano topology (Szakacs, 1994) 4. A quantitative ad-hoc rule: a thorough statistical study of the long-term eruptive patterns of volcanoes and a good knowledge of the eruptive history of individual volcanoes (Szakacs, 1994). Historical 1916, submarine records of volcanic 1867, submarine activities

1853, submarine

1854, submarine Phenomenological Definition A volcano should be considered active if its magmatic plumbing system is still working:

volcano-monitoring networks the existence of possible “active “ magma chamber Volcanic landforms 2 m LiDar of Chihsingshan volcano Ash deposits in Basin

(Chen and Lin, 2000) (Belousov et al., 2010) Stratigraphic relations of the most recent volcanic deposits in TVG W-SW foot of Mt. Cising

Siahu Creek Huangsinei Creek

Pumice-rich lahars Cising debris avalanche Pyroclastic flow – derived lahar  C1411 620 +/- 60 BP  C14 5 400 +/- 50 BP Plinian eruption AshC14 4 11 600 +/- 60 BP with formation of Ash 3 Ash14 2

deposits  C 13 610 +/- 70 BP the tuff ring ? Siaoguanyin Paleolake hot avalanche Ash 1  C14 19 520 +/- 120Shamao BP landslide

Datun debris avalanche Last eruptive age: 5,500 年 (Belousov et al., 2010) Evidence of active volcano -- Phenomenological Definition Volcanic earthquakes in TVG

Lin et al., 2005 Evidence of active volcano

(Yang et al., 1999) Characteristics of volcanic rocks Potential volcanic hazards Mt. Unzen Lahar deposits in 台北盆地井下岩性柱狀圖 關渡井 蘆洲一號井 五股一號井 o o o

N Kuanyinshan Volcanoes -100 -100 -100 10 11 7 km 8 9 2 1 3 5 Linkou 13 t Tableland l t 12 u l -200 -200 -200 a u a F F 16 l g a n 4 19 a m u r o h Taipei Basin c N n 17 i o 15 a 20 s i H h c -300 n 14 -300 -300 a 18 S

-350 沉積物 21

Western -400 火山碎屑流堆積物

Foothills 火山砂及礫互層

火山泥流堆積物 -50 0 五指砂岩層 Dam lake N Tatun Volcan o G ro up Distribution Kuanyinshan Volcanoes Kuantuo 10 11 Beitou of dam lake 7 km 8 9 2 1 3 5 Linkou 6 13 Tableland 12 t l u a 16 F

0 4 19 ang Taipei Basin hu

nc 15 17 i 20 s H 14 18 20 10

21

Western

Foothills

Lahar deposits 10 Shanchiao Fault Var ve Isopach Modified from Teng et al., 2004 Recent survey on offshore of north Taiwan

Volcanoes in offshore of north Taiwan

Gas plume in the offshore -- EK60 acoustic images

Gas Plume Gas Plume Gas plume in the offshore -- EK60 acoustic images

Gas Plume Gas Plume Kueishantou volcano Evidence of active volcano TL age:~ 7 ka

PLUME Fluids around Kueishantao Chen et al., 2001 ) MORB -6 10

Fumarole He (x10 4 He/

3

Bubbling gas Sea water AIR CRUST 1 spring 0.1 1 10 100 4 He/ 20 Ne Mapping Potential volcanic hazards in Kueishantou Krakatau Volcano, Indonesia Santorini Volcano, Greece > 30 m in height of wave > 25 m in height of wave Collapse of volcanic body

NE--SW NE--SW

Unzen Volcano, 1792 Location of Ilan Plain and Kueishantou

Coverred flood area of 5 m rising sea level Thanks!