Phân tích đặc điểm địa mạo tỉnh Lào Cai phục vụ dự báo hiện tượng lũ quét

VIEN D|A LY - VIEN KH&CN VIET NAM HOI DIA LY 'VIET NAM

PHAN TICH DAC DIEM DIA MAO TINH LAO CAI

PHUC VU DU BAO HIEN TUONG LU QUET

Kieu Qudc Lftp'

SUMMARY

Study characteristics of geomorphology in Lao Ctd province for flash flood warning

For mountainouiis areas of Lao Cai province, severed kinds of natural hazards,

such as flash flood, debris, mud flash flood and landslide, present a constant

catastrophic rick. In order to warn of their appearance we can study

geomorphological.

'This paper dicusses the necessary and sufficient geomorphologic, lithologic and

tectonic conditions for flash flood which should be consider as geologo -

geomorphological M-arning sings. It seems the most vulnerable sites coincide with

those areas where exist tectonic .shattered belt, rocks which are easy to be crushed and

shattered fomiiig weathering products heterogeneous and rich in clay material,

availability of thick and abundanl cover of superficial deposits, presence of alluvial fan

deposits, etc.

1. DAT VA N DE

Trong nhfrng nam gan day, ki quel xay ra ngay cang nhieu va gay ra nhfrng thid

hai Idn ve ngudi va ciia. Do nai chju ki thudng la noi phan bd dan cu ddng diic nen

thiet hai cang Idn. Thai gian qua, Ifi quel da xay ra d nhieu nai trong tinh Lao Cai, dac

bid la cac huyen nam tren day Hoang Lien Son, nhu huyen Van Ban, Bat Xat, SaPa.

Lii qud la dang tai bien dac trung va la mgt tai bien nguy hiem ddi vdi mien mii.

Thuc chat ki qud la mdt trang thai dac bid ciia lii cd lien quan chat che den dac diem

dja hinh, dja mao. Tren ca sd nhfrng tai lieu dieu tra, khao sat, md ta cac tran Ifi quel d

Vid Nam, cluing ta Ihay rang;

1 - Lfi quel thudng xay ra nhanh, bat ngd, dien ra trong thdi gian ngan, nhung sire

pha buy lai rat Idn,

- Cac Iran ki quel thudng xay ra vao ban dem va vao dau miia ki, Nhfrng nam gan

day, hi quel cd xu hirdng tang len mgt each rd ret,

- Noi sinh ki la dau ngudn ciia cac con sdng cd do ddc Idn. Nai chju lii thudng la

cira ciia dong chay lain thdi, noi hdi luu ciia mdt vai nhanh sdng. Day thudng la noi tap

Irung ddng dan cu.

- Luu vuc xay ra lfi quel thudng nhd va cd do ddc Idn, ddng chay mat cd ddng

nang Idn, gay xdi mdn, sup Id phd bien.

- He thdng ddng chay bj u tac bdi dja hinh hay cac baric tu nhien hoac nhan tao.

Khi cac vat can nay bj pha buy tbi ddng hi cang hung dfr hon.

Dai hoc Thai Nguyen

Hdi nghi Klioa hgc Dia ly Todn qud'c Idn th&S - Hd Ndi, 2010 833